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by Robert (Bob) Fenner
Good afternoon Crew!
I have a garden pond with two generations of Shubunkins in and I've today
noticed that one of them has a 'sac' between it's anal fin and
caudal fin - it looks like it's full of a creamy type pus with a
few reddish streaks in it, a bit ghastly looking!! The fish itself is
swimming and eating ok but I'm worried that it's suffering - do you know
what this might be and what I can do for it please?
<Have seen these growths many times. Most are not debilitating, and though
some folks treat, even attempt surgeries to remove/excise them, I would not.
Often they disappear on their own>
Thank you for your help!
<And you, Bob Fenner>
Ulcer on 2 inch koi 7/17/17
I have a baby koi in a fairly new pond who has an ulcer on him. I noticed the
ulcer about 4 days ok. The only thing I was able to find locally was
<Mmm; search WWM re this plant extract. Of no real use; may be detrimental to
so I immediately started treating with that while I waited on some Aqua
Prazi to arrive.
<... Praziquantel? Do you suspect this is a worm involvement?>
I now have the Aqua Prazi after using the Melafix for 3 days. Can I use the Aqua
Prazi now, or do I need to wait since I treated with Melafix?
<I wouldn't use either>
The ulcer is not getting better, and the baby koi is not as active as he was a
couple days ago. I tested my water levels and they checked out fine.
<... need values, not opinions>
I will try and get a picture for you. I really appreciate your help. I have had
koi for a couple years, but never have had any problems, so I am kind of lost.
Thank you very much.
<Can you send along a well-resolved pic of the sore? Is it emarginated?
Your small Koi may have (had) a simple mechanical injury; the sore resultant
from the trauma. Perhaps there is/are bacteria here as cause or result. Am
asking you to read here:
and the Related FAQs file linked above. Does your fish's sore look like this?
fiberglass on top of rubber liner for a pond?
Hello and HELP! We recently had a “pond” built in our back yard. I put pond in
quotes because it is more of a reflecting pool than a pond (see photos).
<A very nice job>
It is 2 feet deep, no fish or plants, and has a rubber pond liner with 3 jets
and 4 lights in the pond walls.
<Is it not to be biological? Id est, not have life in it?>
We are not happy with the rubber liner for a few reasons:
While not leaking or causing any problems, the rubber liner has wrinkles along
the walls and in the corners and doesn’t have the sleek contemporary look we
were told by the contractor that it would have once finished
<Mmm; this appearance is really difficult to achieve with liners, particularly
the thicker butyl rubber>
We have black rocks in the bottom of the pond (to help hide the ugly rubber
liner) but cleaning the pond is impossible with the many acorns, heavy
tree/plant pollen, etc. sitting between and underneath the rocks.
<Ah yes... have to drain, remove the rock really to clean. Been there, did this
for several years commercially>
Even when the pond is drained you have to hand pick out the acorns and small
debris from between/under the rocks, which is no small/easy feat.
We’ve been told that fiberglass can be sprayed over the existing liner
to give a smooth surface, but I haven’t found any information about
that process online (much less identified anyone locally that could do it).
<Mmm; I wouldn't do this... the fiberglass will not last, and is toxic in the
short term and a real mess to remove, fix... IF you must have a smooth
surface, DO look into having a "cement plaster coat" (much the same as swimming
pools) applied, likely with some reinforcing mesh (chicken or stucco wire is
what we used to use)... Dark color/oxide can be added to the "plaster", and it
can be smooth troweled... >
We’ve considered just taking the rocks out of the bottom of the pond to make
cleaning easier, but have been told that the rocks might be needed to help weigh
the liner down or it could end up looking even messier/less formed without the
1. Can you “spray” fiberglass over the existing rubber liner of a pond and, if
so, how likely is it that you will end up with a pond that has smooth surfaces
and not look like a mess?
<There are free-standing (pre-fab) fiberglass ponds, and folks who have done
"chop" and layered fiberglass (and resin) basins, and leak repair tries. Our
company's had a good deal of experience with removing these>
2. Any other ideas on how to manage or change the liner to make it easier to
keep clean and look smooth without completely rebuilding the pond?
<As stated above. See WWM (the Pond SubWeb) and/or my books on water features
(avail. on Amazon) for much more>
3. Any other ideas for what to do about the bottom of the rubber liner other
than rocks to make it easy to keep clean yet look good?
<You may not like this... but adding a dye to the water is about all the
alternative I'd consider>
Thanks! Tony Meyer
<Welcome. Bob Fenner>
Goldfish Growth Question
I came across your website and was wondering if you could help me out
with a question. Sorry, I wasn't sure what email to use so sent it to
both the general and your own email.
I noticed some of my pond goldfish have developed some bumps on
I have come to the conclusion that they're carp pox as last year (in
winter) I noticed that the same fish had some ulcers on them so I
treated them with antibiotics,
<Mmm; not of much/any use here IF pox; which is virally mediated>
quarantined them and they all disappeared coming into summer. I didn't
notice that there were lumps last year, more so ulcers into the middle
of winter but I think I've caught onto it early this time.
The weather's getting colder again and we're going back into winter and
these bumps have developed even though the water parameters have stayed
fine/stable (currently at 0ppm Ammonia/Nitrites and Nitrates about
<Mmm; too high. See WWM re Nitrate control; keep under 20 ppm>
I will do a water change to clear the nitrates down, 30ppm General
hardness, 0ppm Carbonate Hardness and pH 6.5):
<No images attached>
I've read there's nothing you can do to treat them except just wait it
out, keep the water clean and support the fishes with a good diet.
<This is about it>
I'm thinking of getting a heater to bring the temperature up into the
summer temps to help boost their immune system and replicate the
environment that they went away in last year? What do you guys think?
<I wouldn't do this... for one, expensive to run/heat large volumes
outdoors; for two, the possibility of heater, electric failure w/
disastrous temp. fluctuation... and thirdly, better to let the seasons
gently cycle coming and going>
Do you agree that it's pox? They're still eating and behaving like
normal but I noticed that it's the exact same fishes that had the ulcers
last year in winter so it probably is viral/pox flaring up?
<Possibly... need well-resolved images to tell more. Might be
Furunculosis, or even just reaction to something/s adverse in the
environment. Do see/read on WWM Re:
and the linked (above) files in this series>
I would appreciate your help!
<Welcome. Bob Fenner>
Re: Goldfish Growth Question 6/18/17
I'll do some reading. The images should be attached now.
<Ahh; they are... and this does look like Carp Pox to me...>
<You should look carefully into your pond conditions ("dirty water") and
do what you can to improve water quality, nutrition. There is no (other)
direct cure (as far as I know). Bob Fenner>
pond mortar 6/13/17
From searching your posts I have found the following two recipes for waterproof
concrete and mortar. Can you please help me decide which is best to use. I
am building a small pond to hold 400-550 gallons of water. I
will be using extremely large river boulders as large as a washing machine to
frame to pond. I will be setting down a liner with stucco wire/concrete
mesh/chicken wire like you described. I want to build as I go, having the pond
be primarily built from large river rock (basketball sized to softball sized).
Question 1: Which concrete recipe or mortar recipe should I use?
3 Aggregate (1/4 pea gravel)
2 Sand (sharp)
1 Cement (plastic cement)
4 Aggregate (1/4 pea gravel)
2 Sand (sharp)
1 Cement (plastic cement)
<I'd go with recipe #1, less aggregate... Three parts here will be enough>
Question 2: Is there a foundation coating, cure retardant or additive I should
use that will not change the color too much of the natural stone (clear coating
is ok, shiny is ok, white is not ok).
<Mmm; no coating... mask off (paper or trash bags, tape) and try to not get too
much cement/concrete on the rocks... sponge (large yellow ones at the concrete
place) what you can while it's still wet... read on WWM, elsewhere re acid
washing to remove the rest after all is set>
Question 3: There is not a home depot or Lowes around me that sells “plastic
cement”, I live at 10,000 feet in Colorado. Can I make my own “plastic
<Mmm, well; you can/could add plasticizing materials (such as limestone,
hydrated or hydraulic lime); be careful with the last two (wear a breathing
mask, gloves) as they're very alkaline...>
Question 4: There is one concrete producer an hour away that sells a “shotcrete”
mix with the option of an additive mesh of some sort…would this work?
<Yes... but this term refers only to the fact that the blend is intended to be
applied by high pressure...>
<All these types/kinds of concrete will work for you here. I suggest putting the
liner and wire down... having friends over to help mix and apply whatever you
end up with. Take your time. Bob Fenner>
Re: pond mortar 6/13/17
Wow! Thank you! I looked to see if just hydrated or hydraulic lime was available
and no, it’s not. I have only used pre-mixed mortar in the past but I want to
use your recipes and advise.
Question 1: Would this mix below work for the rock work I explained or should I
add more less of something?
1 bag- CEMEX CEMENT MIX/TYPE S- PORTLAND CEMENT-LIME MIX-70 LBS
1 bag- SAKRETE PORTLAND GRAY TYPE-I/II CEMENT MIX
5 gallons of water (give or take)
18 shovels of aggregate/sand (I have sand from an old river mining operation. It
is bank run dirt, washed and classified to half an inch, therefore everything in
the sand is half inch and smaller) Would this count as my sand and aggregate
both or just sand?
<Better to have sand AND aggregate... and for such a small pond/basin,
"pea gravel", nominal 1/4" diameter. Half is really getting to be too
big. IF you can, you want to keep the wall thickness down to 3-4"... easier to
do w/ smaller grade gravel. The mix ingredients are overall okay...
again, see y/our prev. email for relative volumes. 3:2:1, and just enough water
Another option is that I buy pea gravel and crush some rocks in a rock crusher
(I have plenty of large rocks to crush)
<Yes... or likely easier (what I would do), sieve out the too-large bits, use
them elsewhere (as in a mix for falls...)>
<And you, Bob Fenner>
contacts, Not saved on WWM 6/13/17
Dear Wet web I know this is an unusual request.... I was reading your Q and
A's and I noticed there was a question from a help with converted
pool; algae posted on 7/2/15
...Dear Bob Fenner and Crew,
Howsit Lou Anne?...,
from Pasadena, ca, well I too, live in Pasadena and have converted my 25000
gallon pool into a pond with turtles and fish. I am having the same problems
(we seem to have started our conversions about the same time) I would love
to get in contact with her and talk about our ponds, can you please contact
her and give her my info
Tamara XXXX com
I would really appreciate it. With many people wanting to do this pool
conversion I was hoping that there will soon be a form for just this
particular project. thank you so much
<We don't retain folks contact information unless they expressly request to
post it Tamara.
Do please peruse the files archived on WetWebMedia.com re pond algae issues
and swimming pool conversion. Bob Fenner>
Help!! Fantails with disease & growth
Hi Neale/Bob -
Firstly, thanks so much for such a helpful and informative site. Having never
previously owned fish, your site has assisted us in having our 18 fantails
thrive in a 3500L outdoor pond for the last 7 or so years without incident, with
a few babies also :)
I am writing because I have two fish I am concerned about (for different
reasons) and, despite trawling through your site, I am no closer to being sure
what the problem is. I am therefore reluctant to do without knowing exactly what
is wrong. One has a growth, and the other has two white spots.
Incidentally, they are both the oldest fish in the pond.
Flippy is the matriarch who has all the babies, and over the last several months
has developed what looks like a benign tumour. It started with scale
discolouration, then scales lifting, then the cauliflower-like growth that is
<I see this, and agree re this being a growth of some sort. Some folks might try
excising this (essentially cutting away with a scalpel) and daubing the area...
I would leave it be>
She is otherwise happy and healthy, and eating normally (see photos attached).
Houdini is a master of survival, and lived in the shallows of the pond without
our knowledge for approximately 18 months before joining the main pond about 7
years ago! He has very recently developed two white spots/growths on his side,
but is otherwise happy/healthy and eating well. He does not seem to be
exhibiting any strange behaviour (rubbing, scratching etc).
<Can't tell what this is... as it's only on the one fish... Perhaps simply a
manifestation of a physical trauma; I would NOT treat for this>
The pond has a dirty water pump with UV filtration, which does 12000L/hr. We use
Wipeout for bacterial control (though we have only ever had to use this once or
twice), water conditioner in summer when the pond loses water at a faster rate,
and Coptrol (aquatic Algicide with 107g/L mixed copper chelates) as needed to
<Mmm; the last is dangerous and perhaps a factor here... stressful to/for the
I'll admit we have never needed to use testing strips in the pond, so I cannot
tell you what our levels are, but the other fish are all happy, healthy and
disease free. The water is also clean and clear to the eye. We do have a lot of
detritus in the bottom of the pond (by design), but do control this with regular
and gradual clean outs as required.
<Good; I like this last description/practice>
There is <sic> water lilies and water reeds in the pond, and the fish are fed
pellets from our local specialty fish, pond and pump supplier. They are fed in
the afternoon every second day (there is rarely left over food), and seem happy
with this. To the best of my knowledge, they have always been healthy and happy
in the pond. Until now, really the only issue we have ever had is with Ibis (a
local water bird) coming in and trying to steal fish (hence the netting in the
Just in case it is relevant, I am in Perth, Western Australia and we are just
going into our winter. These are generally quite mild - today it is sunny and
fine, with a minimum of 8 and a maximum of 23 degrees Celsius (the average range
in winter is 8-19).
<Sounds good; I would cease feeding pondfish when the temperature stays less
than about 50F/10C.>
Any advice or assistance you can offer would be sincerely appreciated. <As
above; I would likely stick w/ your stated routine and not add anything more>
<As many welcomes. Bob Fenner>
Re: Help!! Fantails with disease & growth
Hiya Bob -
Thank you so so much for such a speedy response! And sorry about the file
size *hangs head in shame*
I will do exactly as you advise, and also look into another option for algae
We were obviously ill-advised when we were told this was safe for fish.
Thanks again -
<Glad to help. BobF>
Algae Growth on Water Lilies... New pond, and ponder
It's Fuzzi here, again, with a question I can't find answered on WWM, or
anywhere on the web, so I decided to ask!
I installed a 100 gallon preformed pond this April, adding water on
April 16th, then adding filtration a week later, on April 23rd.
<So; just a month back>
I'm running a 330gph submersible pump, a skimmer with basket and filter pad,
and the waterfall is full of floating plants doing their best to filter out
the less-than-clear water, see photos. It is not noticeably green
until you collect some in a jar, when a slight yellow/green coloration is
<Happens... a sign of life... not to worry>
Since I added filtration, I have been steadily adding plants in pots, as
well as floating plants (water lettuce and hyacinth), and then two hardy
water lilies about two weeks ago. The weather has remained cool until
No fish have been added.
I noticed that the water lilies have a green slimy algae-type of growth on
their stems and under the pads (see photo).
The water tests as uncycled, high (above 7.6) pH, ammonia, nitrites, and
nitrates as zero.
<Uncycled... these should be some nitrogen present>
I believe the algae growth is due to new pond syndrome, but would love your
1. If the algae growth is part of new pond syndrome, will it pass once the
2. Will it hurt the water lilies?
<It will not>
3. If it will hurt the water lilies, what can I do about it?
<Patience at this point. Your pond may well "green out" for a while... best
to shade a good part of it>>
The lilies are planted in clay dirt in plastic baskets, with paper lining
the inside and pea gravel on top to keep the dirt from leeching out. Each
lily has one fertilizer stick shoved down deep in the pot, on the side away
from the rhizome.
Thanks for your advice and thoughts on the algae situation.
<Don't get desperate and chemically treat... algicides are toxic; directly
and in their effects. Bob Fenner>
Trouble calculating my pond volume
I am trying to figure out the volume of my irregular shaped pond. I got 3
different measurements on it. One for the shallow end (2'Lx5'Wx0.1'D), my second
deepest part (5'Lx8'Wx1.6'D), and my deepest part of the pond (3'Lx
6.9'Wx3'D). What is the volume of my pond in USA gallons?
<Mmm; multiply all three measurements... add for cubic feet, multiply this by
7.5 (gal.s/cu ft.), done>
I am having trouble calculating these measurements due to a math disability. Can
you help me with this one? Thank you.
<Otherwise, time how long it takes to fill a given volume container (like a five
gallon plastic bucket) and measure the time it takes to fill the basin. Bob
Subject: Cement Koi Pond Question 4/16/17
I have literally been reading for months and stumbled upon your website quite by
accident. I have now dug and ":shot" my cement (gunite) Koi pond.
I remain confused. Should I Plaster the pond or coat the gunite?
<Either way.... but needs to be sealed... to render water tight and prevent much
I did NOT use a liner prior to shooting the gunite. The pond is 25 x 15 x 5
<Mmm; as you likely know from the reading; I am a huge fan of liners. Let's hope
your basin/s don't leak, the ground doesn't shake, shift, allowing cracking.
Cheers, Bob Fenner>
Re: Cement Koi Pond Question 4/16/17
Thank you for a very direct and "straight" answer....
<Ahh! The way I am. Cheers, Bob Fenner>
Gunite Koi Pond? 4/23/16
Search as I may, I can't seem to get a straight answer. Can you tell me
if GUNITE is toxic to Koi fish.
<Mmm; gunite is actually a mortar... a mix of cement, sand and little water.
It's the delivery of being applied through a pressurized hose that makes it
different than mortars applied by hand. DEPENDING on the type of cement used
(some are quite alkaline), gunite can be more/less toxic to koi and other
aquatic life. Did we chat before? Gunite ponds, swimming pools, spas
MUST be coated to make them waterproof AND PERHAPS less toxic. In the pool/spa
industries the term "plaster coat/ing" is used though this (plaster) is not what
in fact is applied... I would look into the Thoro line or similar products here
to seal the gunite>
I am building a 10,000 gallon gunite koi pond in my back yard. I have discovered
an article that states GUNITE it toxic to koi. I have read about other sealants,
and noted that others have veered away from Pond Armor. So here are my two
questions, N 1) MUST I seal my gunite pond and 2) Can I "plaster" my pond walls
prior to any sealing using after plaster Pond Armor application?
<Yes and yes>
<Welcome. Bob Fenner; whose old businesses at times dealt with gunite
applications for biological systems>
Re: Gunite Koi Pond?
Thank you for a "straight" response....
<Glad to provide it. BobF>
Pond Pump Question 4/14/17
The last time we "talked", I had an injured Kuhli loach, but it appears to
have recovered, without use of antibiotics, but only using frequent water
changes. Thanks for your input!
Now, my question(s):
I've recently noticed that you have a pond section of WWM, woo! After
reading most of the articles about ponds, and using the internet, AND
researching with (!!!) pond books, I still cannot figure out something, and
am hoping you can help me:
About three years ago I purchased and installed a 20g preformed pond. It has
a waterfall and pump that have served well, with filter media located in the
top of the waterfall. I am upgrading to a 80-100g preformed (approximate
size as it's second-hand, irregular shape, and I won't know the exact size
until I add water).
A couple years ago, in anticipation of a pond upgrade, I bought a brand new
Gen-X GX-6000 submersible pump (great sale), and am now getting ready to
install it in the new pond. However, I can't figure out how it works, as it
only has one output nozzle (see photos). There were no instructions, as it
was sold "out of box", with just a portion of the original packaging
remaining (see photos). I have spent many hours scouring the Web for a
users' manual, without success.
Could you clarify how this design works? The websites I've gone to are not
The printing on the side of the pump reads:
GX-600 Submersible pump, AC110V, 60Hz, 130W, Hmin>0 Hmax, 3.8 Qmax, 6000L/H
The box states the pump has a ceramic shaft.
Thanks so much!
Sorry about the quality of the photos. I hope they are clear enough: I used
<The three threaded by ribbed connectors are for variously fitting discharge
(the top) for attaching hose for... waterfall or jet for fountain on the
discharge (top). This pump is designed for producing more volume and
pressure than the application you have in mind here... To repeat: this may
well prove to be too much pump for what you have intended here... IF you
find that too much water is being moved about, you might want to look into a
smaller unit. Bob Fenner>
pond goldfish with one showing blisters
I have aprox 3000 gal recirculating pond with waterfall. There are 7 adult
goldfish (2 comets, 3 Sarasas, and 2 Shubunkins ranging from 6 to 8 inches)
as well as 4 fingerlings, (native frogs that I can't keep out) and a variety
of water plants. I just had the spring cleaning done by a professional
(which included replacing the water) last week. There is 1 functioning
aerator (a second one is waiting for repair). We also replaced the Triton
ionizer anode but the controller doesn't seem to be working so are waiting
for parts to replace that as well. I live in Texas. We had a gentle winter
so they never truly hibernated this year. Our spring/summer warm-up began in
March and they have become correspondingly ravenous. I don't feed them daily
but when I do, I use Tetra season appropriate food. I converted them to the
summer food when the water temp reached 60 a few weeks ago.
<With you so far>
Today (April 4) I noticed that the largest Comet has aprox 5
blisters (none of the others have any that I can detect). I last
fed them on April 1 and didn't notice any blisters. The comet with the
blisters is currently acting normal. It is the largest of the fish and the
most voracious eater.
<Could be... nuptial (breeding) tubercles (do look up)... As none of the
other fishes are showing such, I doubt if there is an environmental or
pathogenic issue. I would do nothing at this point... but watch the one
fish for reproductive behavior. Bob Fenner>
Thanks, Sharon Nilsen
Re: pond goldfish with one showing blisters 4/5/17
Thanks so much for a quick response! Will monitor.
<Please do keep us informed. BobF>
Deer Vs, Water Lily
Greeting WetWebMedia Crew, I'm currently moving to a new property and am
transporting a fairly water lily collection over. I've been told by previous
owner they have a fair amount of axis deer moving thru property.
Do have any predictions on how the water lilies will fair. The house actually
has 2 in-ground ponds and I'm moving some above ground stock tanks over. Do you
think the deer will be very attracted to the water lilies or do they have a
chance of co-existing without netting and/or fencing?
<Mmm; Axis deer will eat water lilies. Whether yours are attractive to this
particular bunch though remains to be seen. You'll definitely notice in both
cases. Bob Fenner>
Re: Deer Vs, Water Lily 3/19/17
Thank you for reply Bob. I actually dropped off a few stock tanks with water
lilies yesterday and wont be back for a few days. I'm hoping once my dogs move
onto property they should keep the deer away but in the mean
time, I'm a bit worried. I'll keep you posted with any developments. Thanks for
the great site.
<Am with you. Had the local deer eating my Avocado tree leaves... tried the wolf
pee product, shiny ornaments... Finally fashioned four by welded wire (for
driveways) around them. Then the price of water quadrupled!!! BobF>
One last question on my 40 gallon pond I am planning.
Overwintering small pond 3/8/17
As you know I have a 40 gallon pond I am planning. I want one fancy goldfish
in the pond. The pond will be outdoors. I live in the subtropical desert
region of the AZ desert. I might use common fantails, as they are hardier
than most fancies. But I have got that Ranchu in my big 765 gallon pond
right now. She is with 9 comets, 1 comet Shubunkin hybrid, 1 Ryukin, 2
common fantails, and 1 Oranda. She is very nervous right now. Just got her
about 3 weeks ago. She is also the smallest and slowest fish I have. I am
making sure she gets all the food she needs. But she concerns me the most
out of my fish. I may I have to take her with me if I move anywhere. Or I
may have to put her in this new pond I have planned. The whole purpose of me
obtaining this new pond is so I can take one fancy goldfish with me if I
have to move. It might wind up having to be the Ranchu. The Ranchu needs me
the most. This pond must be able to work outdoors for any fancy goldfish I
have to take with me. Any suggestions on insulating the pond or
warming it with a heater during winter?
<Put it indoors, like in a garage during the cold months of the year (when
nights are below 55F let's say) is what I'd plan on doing. Bob
RE: One last question <?> on my 40 gallon pond I am planning
Garage is not an option either. Anything else I can try?
<Spray foam on the outside? Building a wood box and lining it w/ Styrofoam
and placing the pond inside? A submersible heater set on low? B>
Here is a photo of my 40 gallon pond I plan to use.
and the linked files above.
RE: One last question on my 40 gallon pond I am planning
Will try those ideas. Thank you so much Bob! ��
40 gallon pond Photo and Bubble wrap question 3/8/17
Here is a photo of the 40 gallon pond I have been talking to you about.
<... you already sent this>
Would bubble wrap work as temporary insulation too?
<Doubtful; IF the temperature vacillates too much diurnally; there will be
trouble... Too much stress. I'd just keep the fancy goldfish indoors in an