F8 brackish water questions. Fig 8 sys; salinity... Artemia cult.        9/22/16
Hello guys!
<Hello!>
I know there's a lot of info already about this subject on wet web media and I have studied a lot of it. Thanks so much for all you do. I'm emailing you because I feel that I have a specific problem that I would like help with. About a day and a half ago, we bought a Figure-Eight Puffer. He's a little over an inch long, so what do you think...maybe about a year old or a little less?
<Sounds about right.>
He's in a 40- (US) gallon aquarium. All basic water parameters (nitrites and ammonia) = 0 except pH=7.6 and nitrates are <20. The aquarium is well-established. It was a freshwater setup for Gouramis and Tetras, but they have been moved to a different tank.
<Understood.>
Anyway, I was unaware (until reading your website last night) that you can't just use API Aquarium Salt to create brackish water.
<It's okay short term. Better than no salt! But longer term, actually not economical or as good. Better to use marine aquarium salt.>
I added a teaspoon per gallon of that yesterday. Then I went out today and got some Instant Ocean after discovering on your website that this is what I need for making proper brackish water.
<Ah, good!>
One question I have is: Will it be necessary to do a large water change, say 75%, to remove as much of the API Aquarium Salt as is possible before adding the Instant Ocean?
<Nope. Your little Puffer will be absolutely fine as he is now. Just add your marine aquarium salt to each bucket of new water added to the tank.
I'd suggest adding 5-6 gram salt mix per litre of water. That should produce about SG 1.003 at 25 C/77 F.>
Also, how much Instant Ocean should I add to make brackish water with an sg = 1.002? (I read on your site that you should gradually introduce him to brackish water if the pet store had him in freshwater, increasing it to 1.005 over 3 days.)
<Correct; and see above.>
My hydrometer is reading just barely above 1.000 right now.
<That is because 1 teaspoon of salt per US gallon is a trivial amount of salt. Not brackish at all! Full strength seawater contains 35 gram salt per litre. That's about 6 teaspoons of salt! Most people have no idea how salty the sea is. You only want a fraction of that amount of salt. One teaspoon is about 6 gram salt, so a bit less should be 5 grams, and that's the
amount to add per 1 litre of water to get SG 1.002-1.003, which is ample for a planted low-end brackish system.>
He's a really cute little guy, very inquisitive, very active and we have a good supply of pond snails for him. I plan to vary his diet with frozen Tubifex and freeze-dried Krill. As for our snail supply, they live in my male Betta's tank where the pond snails run amok and he never bothers them!
My female Betta eats all the snails in her aquarium!!!
<Cool!>
I also was wondering if it would be possible to breed brine shrimp in the puffer's aquarium since it will be brackish?
<In theory, yes; in practise, the filter will suck up the brine shrimp eggs before they hatch, so nothing will happen.>
Or am I remembering correctly that you said that they have very little nutritious value for a puffer?
<Adult brine shrimp are a poor food. Baby brine shrimp are much better though, and you can hatch these in an empty plastic Coke bottle (or similar!) filled with seawater (35 gram/litre) and bubbled a bit with an airstone. Even easier, buy some "enriched" frozen brine shrimp; these are a good food for puffers.>
If so, maybe it wouldn't even be worth it. And, is a 40-gallon aquarium large enough for two F8 Puffers to coexist without fighting?
<Actually, I'd keep three specimens rather than two. Pairs can squabble much worse than larger groups.>
I have heard yes and no from so many different people on that question.
<Indeed; all puffers are unpredictable, at best. But generally bigger groups are less troublesome, but of course need you to be extra careful about water quality.>
Thank you again for all your help in the past and in advance for your answer to all this. Sorry to have written a novel here, but I felt I needed to explain the situation in detail.
Riobbcah
<Hope this helps, Neale.>
Re: F8 brackish water questions       9/23/16
Thank for the info. This helps me a lot. One more question if you please.
Do you use a testing kit for salt or for fresh water in the case of a brackish water setup? Thanks!
<Yes, you can use your freshwater test kits in a low-end brackish kit. The only problem might be pH or hardness kits "going off the scale" because the pH and hardness might be above the range of colours on the card you compare your test result to. But the nitrite, ammonia and nitrate kits are fine,
and chances are the pH and hardness will be fine too. Cheers, Neale.>

Live blackworm colony in brackish water?     6/11/16
Hello WWM,
<Hello Meghan,>
I am in the process of setting up a brackish tank for a violet goby I purchased before doing adequate research. So now I'm trying to make sure I get it right so I won't have to move "her" once in brackish water.
<Wise.>
Currently she is housed (I know inadequately) in fresh water in a 55 gallon with several dozen guppies.
<A surprisingly good combo! Violet Gobies seem to ignore the adults, and any impact on the baby Guppies seems to be trivial and accidental.>
Her current water parameters are pH 8.2, very hard water.
<Excellent.>
When I test the ammonia is always 0, nitrite 0, and nitrate never over 20.
I use a thick (3 - 5") layer of organic dirt and sand that releases a lot of tannins into the water. She loves to dig, dig, dig!
<Oh yes. They also enjoy gulping plankton (such as live brine shrimp) as well as scraping at algae-covered rocks. They're very interesting animals.>
I love the look and behavior of this beautiful little goby. She seems to be doing well, despite being housed in fresh water, and has grown 3/4" in the last 3 weeks. I enjoy watching her dig and sift for food, so want to make sure her permanent home encourages this natural behavior.
<Yes.>
To this end I'm wondering if I could culture a self-sustaining colony of blackworms in her eventual home.
<Almost certainly not. Lumbriculus don't have a very high tolerance for salt; if you use Google Scholar and search for "Lumbriculus" and "salinity" you'll find a fair amount of experimental data. While they would probably do okay in low-end conditions, around SG 1.002-1.003 say, they're unlikely to prosper at higher salinities. Bear in mind Blackworms are freshwater Oligochaetes, and specialise in freshwater habitats. Once the environment becomes brackish or marine, Oligochaetes become much less significant players in aquatic ecosystems, being replaced by the Polychaetes instead,
many of which are euryhaline and able to adapt to changing salinity environments.>
If I introduce them into the substrate and feed them in fresh water, then slowly make the transition to brackish water do you think they might adapt and survive?
<I would not put money on it, and a bunch of dead worms in the sand isn't going to be much use to your water quality! In any event, even if they did survive, I doubt they'd maintain sufficient populations to feed your Goby.
You'd need many square metres of mud for that.>
Ideally I'd like to get the specific gravity as close to 1.010 as possible for the health of the goby, but I might be willing to stop at a lower salinity if acceptable to both worms and goby.
<Violet Gobies are euryhaline, and as happy at SG 1.003 as they are at SG 1.010. As you have seen, they're quite hearty animals! They come from mudflats and actually have the ability to survive in mud when the tide goes out. What kills them is the total absence of salt over long periods. Once you get into the brackish range, they're pretty much happy with anything!>
Any info or advice will be much appreciated!
<Most welcome. Neale.>
re: live Blackworm colony in brackish water?     6/12/16
Neal, Thank you for your prompt, good natured, and incredibly informative reply. :)
<Most welcome.>
You mentioned that the blackworms might survive at SG 1.003 and that SG 1.003 would also be an acceptable salinity level for the goby, with the caution that dead worms would be bad for water quality if they can't take the salt.
<Correct.>
Rather than throw in the towel over water quality fears, I propose a little experiment. I'll set up a small spare aquarium I have with a layer of dirt and sand, a filter, etc, as I would for the larger goby tank - but all in miniature.
<An excellent idea.>
Then add a Blackworms culture and fresh water. Every 5 - 7 days add a small amount of water with marine salt dissolved in it. I'll do some calculations and decide how much water to change each day and what SG to add. I think two weeks to target SG seems okay. If the worms survive use them as the seed population when I set up the permanent goby tank.
<Indeed. Or else simply culture the worms in ideal conditions indoors or even outdoors in a "water feature" of some sort, and then add the worms to the tank as a periodic treat.>
As to your statement that I'd need several square metres of mud filled with blackworms to adequately feed my goby, I figured with her potential size and huge current appetite I'll have to continue my routine of 2 - 3 times a day feedings.
<Oh, certainly yes; at best, any "in aquarium" colonies of food will be a mere snack, not a staple. Have you come across the book "Dynamic Aquaria"?
Not an easy read, being aimed at academics setting up ecologically balanced food webs in aquaria, but full of useful information. One of the major themes is the HUGE amount of space required to produce sufficient quantities of prey for even relatively small fish such as freshwater Angels. Off the top of my head, it's something like 100 gallons for a
single Angel, that sort of ratio. Of course you're not proposing that, I know, but I'd be surprised if the blackworms were able to maintain much of a population in even a 55 gallon tank alongside an adult Violet Goby. So even if they survive, topping up the supply with ones from another tank or pond will surely be essential.>
I don't want her to mow through the entire Blackworms population at any point, I just want them there for her to nibble to discourage boredom. I know most fish are opportunistic feeders, so all my trouble might be eaten in one glorious afternoon, but if the worms survive the salt I'll keep some of the test pop population aside in brackish water to culture and feed as treats. Let me know what you think :)
<See above. Definitely worthwhile, and a fun experiment, but skeptical of long-term success. Cheers, Neale.>
re: live blackworm colony in brackish water?       7/26/16
Hello Neal,
Thought I'd update you with the final outcome of my salty blackworm experiment.
<Sure thing!>
I set up a 20 gallon long tank with a decent colony of blackworms in fresh water. Organic soil and sand substrate, seeded (cycled) mini corner matten filter, and some rocks and fake plants. Then for two weeks I raised the specific gravity by .001. At two weeks all was going well and the SG was 1.002. The worms were really taking over - looked like a little forest sticking out of the dirt.
<Neat.>
My violet goby, in the mean time, was wreaking havoc on my 55 gallon.
While all had seemed fine for a while, silt from all of its digging had built up in the filter and began repeatedly clogged my matten filter to the point of zero water flow.
<Ah, yes, I can understand this. With big/jumbo fish, it's often easiest to
stick with relatively coarse media. Physically remove silt during water changes rather than relying on the filter. Turkey basters are a good tool for "spot cleaning" piles of uneaten food or faeces without having to waste more than a few minutes.>
I was doing daily 25% water changes and using a wet/dry shop vacuum to remove as much of the silt from the filter foam as I could. With such restricted water flow the ammonia and nitrite began building up, too. The guppies seemed oblivious of the poor water quality, but Kappa (my goby) was looking sluggish and red about the gills.
<Yikes! Do bear in mind these fish are facultative air-breathers. They're actually pretty tough, able to survive in burrows in the wild. Of course one adaptation to this might easily be becoming sluggish to conserve oxygen.>
So I transferred my goby to the 20 gallon (which had better water quality - 0 ppm ammonia, 0 ppm nitrite, and (if I'm remembering correctly) 60 ppm nitrate.)
Kappa promptly swam several circles around the tank, then dug under a rock.
<Cool.>
Over the next week the 20 gallon long's water quality declined. I suspect this was due to an insufficient population of beneficial bacteria to deal with my Goby's size and messy eating habits. Kappa also did its best to clog up the filter by digging through nearly every inch of substrate. Luckily I'd used a thinner piece of filter foam for the corner matten
filter and it was easier to keep clean.
<Yes.>
So just a caution to anyone considering violet gobies in a planted tank - skip the dirt! Your water will be forever cloudy and your filters forever clogged with silt. Instead do washed sand. It seems to work fine.
<Correct. Clean substrate and coarse filter media. Heavyweight filtration as well, but you know that by now!>
Kappa seemed to really enjoy snacking on the blackworms at first, but once the water quality stated to decline, its appetite did too.
So I was back to a sluggish, red-gilled goby in a muddy looking tank. I was doing tons of water changes - sometimes twice in a day to lower the ammonia and nitrite.
With all the back and forth water buckets, eventually the inevitable happened - I miscalculated the amount of marine salt to add to get to my target SG (by now I was up to 1.003) and got it too salty.
<Oh?>
I knew pretty quickly - the worms shot up out of the sand and flopped over.
Some crawled around like they were looking for a way out...
<Correct analysis.>
As quick as I could I got the salinity down with another water change - this time with no salt. The worms settled down. Kappa looked positivity ill. I stayed and watched for a couple of hours, hoping all would be okay.
Then finally went to bed about 3 in the morning. I didn't record the SG that night - but replaced about 10 gallons - so about 1.002 I'm guessing.
In the morning I went in to find the aquarium lid in the tank and my cat looking very pleased with herself. Panicked, I took out all the rocks and fake plants, even the filter looking for my goby, but couldn't find it.
Cautiously I felt through the substrate (I'd heard violet gobies can give quite a bite) but found no Kappa. I sat down and cried.
A few hours later I went back in and there was Kappa swimming around! I'm guessing it was buried in the dirt and I missed it somehow.
<See above. When stressed, they dig burrows. Like lungfish.>
Now the goby is in yet another tank at around SG 1.005 - there are no worms or live plants to worry about, so I'm sometimes imprecise with my salt measurement.
<Which is fine. You can transfer Violet Gobies from fresh to marine and back again and they'll be fine. They inhabit mudflats where the tide comes and goes, and sometimes they might be under a river, sometimes under the sea, depending on the time of day. As you can tell, selling them as freshwater fish is extremely misleading!>
However the water quality is great and its gills are no longer red and its eating and growing very well. The substrate is washed black sand - with a "dam" of aquarium gravel up against the bottom edge of the matten filter foam to keep Kappa from digging under and getting stuck halfway (which it did before I added the gravel).
However, I consider the salty blackworm tank a partial success. The worms were at SG 1.003 for nearly a week and thriving.
<Cool.>
Kappa didn't manage to eat them all, but might have if it had felt better.
<Possibly.>
However, I learned just how easy it is to get the salinity level incorrect and for that reason I don't think I'll try to establish an in-tank blackworm colony in brackish water in the future.
Overall an informative and exciting experiment!
<Agreed; armchair speculation on my part is all very well, but an experiment will usually provide the facts! Within reason of course -- senseless stressing or killing animals for the sake of curiosity isn't something I condone. What you were doing here wasn't that, and I'm pleased you were able to maintain worms and goby with success.>
Thank you for your guidance!
- Meghan
<Welcome! Neale.>

Brackish Tank Questions; stkg., substrate, fdg.      4/15/16
Hi, I haven't had an aquarium in a while and I'm thinking about getting back into the hobby. In particular, I'd like to start a low-end (SG 1.002-1.003) brackish community tank in the 29 gallon aquarium sitting empty in my basement. I have some questions relating to stocking, substrate, and feeding.
<Fire away!>
First off, my tentative stocking plan is:
(1) Peacock spiny eel (Macrognathus siamensis) OR (1) Barred spiny eel (M. panacalus)
<Either should work here, though Macrognathus pancalus is arguably the more truly brackish of these species. Neither will want much salt though; 1.002 should be ample. Lower salinity will also ensure plants can grow well, especially Indian Fern, a definite plus here for stopping Spiny Eels from being jumpy.>
(1) Male and (2-3) female short-finned mollies
<Yep.>
(2) Orange Chromides
<Generally fine, though as territorial as any other cichlid of this size.>
(1-3) Knight gobies
<Nice fish, and will ensure no baby mollies survive!>
Would this be overstocked?
<Nope. Busy, yes; overstocked, no. Just keep on top of filtration and water changes.>
I'm also concerned that in a 29, a pair of Chromides might become tyrants if they decided to breed.
<Always a risk.>
If you think that would be the case, I'll either reduce the Chromides to a singleton or remove them from the plan completely. (If you think this setup would be overstocked, they're also my first choice on what to eliminate.) I'm also wondering if even provided enough hiding spaces, the 29 might be too small for multiple knight gobies. How many do you think would be ideal for this setup?
<Two females and a male should be okay.>
On to substrate, I have a bag of CaribSea Sunset Gold sand laying around my house. Would that be soft enough for the spiny eel, or should I stick to buying some silica sand?
<I've not handled this brand of sand personally, but if it feels smooth rather than sharp, it's probably fine. That said, pool filter sand/smooth silica sand is so cheap, you might want to play it safe and go straight for that.>
Additionally, what depth of sand would be best to allow the spiny eel room to burrow but not to risk anaerobic decay? Does 2" sound about right?
<Sounds fine.>
As for feeding concerns, I want to make sure that the plant-based foods for the mollies and the meat-based foods for the other species wouldn't cause any health problems if the other party ate some of it. I also would like
some advice for feeding a balanced diet to the spiny eel and knight goby.
I know that spiny eels go crazy for earthworms, and I suspect that the knight goby would enjoy them, too.
<Yes! Very much so. Knight Gobies are very much predators.>
However, I'm a bit confused as to which of the big three in aquatic feeder worms (bloodworms, blackworms, and Tubifex worms) is most nutritious and least likely to carry diseases.
<Not much in it, to be honest. Tubifex have a very bad reputation, probably justified. But bloodworms and blackworms aren't exactly cultured in crystal clear pools of French mineral water! On the other hand, if gamma
irradiated, they shouldn't carry any pathogens, and if used sparingly, the risk from introducing heavy metals, for example, shouldn't be too serious.
That said, marine aquarium foods like krill and fortified brine shrimp are certainly safer and usually accepted readily.>
I've seen claims in favor of or against all three of them, even here on Wet Web Media. I'd sort of like to start a culture of one of these in one of the smaller empty tanks as an easy source of live food, but I don't know which would be best for the fish.
<If you're growing them yourself, they're probably all reasonably safe.>
I intend to buy wet-frozen krill as another food for the goby.
<Wise.>
Do you think that the eel would also eat those?
<Yes; spiny eels are hesitant feeders, and nocturnal to boot, but they aren't over-fussy. My specimens have happily taken chunks of prawn, for
example.>
I also know that any and all molly fry will probably end up knight goby
food.
<Oh yes!>
What other foods would be good for one or both of them?
<See above.>
Some of the things I commonly see suggested, such as lobster eggs, aren't available in my area as far as I know,
<Do try stores aimed at marine aquarists.>
and others, like tilapia, I don't think my parents would approve of buying seafood sold for human use to feed to pets.
<So far as seafood goes, one approach is to buy white fish or squid for yourself, and wrap the scraps in some aluminium foil and place it in the freezer. Your fish aren't fussy, and for a few weeks at least such scraps will contain sufficient useful nutrition.>
If I do get the Chromides, I plan on using one or two brands of cichlid pellet or flake food for a staple, in addition to the smaller varieties of worms.
<Yes.>
Finally, for the mollies I'll provide some sort of spirula-based flake food, and maybe algae tablets, but I'd also like to give them fresh veggies. When I see stuff like this mentioned, I always hear that you should blanch the vegetables and put them in the tank when they've cooled off, but I never see any recommendation for how long to cook the veggies.
Is there some sort of good rule of thumb for that?
<None. The blanching thing is about softening, not cooking. Zapping lettuce in the microwave for a few seconds usually does the trick. But lettuce is nutrient poor and shouldn't be anything more than a "salad bar" that goes
along with the main course, i.e., the good quality flake. Some foods, like cucumber, can be left in the tank to soften naturally, and the fish will peck away at over time. Since these foods contain near-zero protein, their impact on water quality is minimal, even if they end up as horrible mush.>
Thanks for the help.
<Welcome. Sounds a nice tank and well planned! Cheers, Neale.>