Danio Problems
Hi,
I started off with 5 Zebra Danios and 4 Peppered Corys in a 70 litre tank and I'm now down to 2 Danios. About 5 months ago one of them got really bloated overnight and I found him the next day looking like his stomach had burst. Last week another one bloated up and then dropped dead within two days. Last night though, I noticed another one carrying what looked like a bruise on his side, he looked red beneath his skin then this morning he was dead on the substrate with what looked like two, small skin bubbles protruding from his underside. <Hi Dave, Don here. Two things come two mind. Let's hope it's a water quality issue. Do you check your water for ammonia, nitrite and nitrate? Any amount of the first two could be the cause. But, if you see any Danios showing a bend in their spine you have TB in your tank. If so, then the fish will have to be put down and the system sterilized. TB can spread to humans with a break in the skin. Be careful and wear gloves. There are also other bacterial infections that can cause this. If the spines are straight, try a good broad spectrum antibiotic. Oxytetracycline may help. Like I said, let's hope it a water quality issue>
I replace 5 <less than 10%> litres of the tank water every 7 days and the tank looks clean but there is obviously something going wrong somewhere.
Any advice would be more than appreciated as I really don't want the fish to suffer any more. <First thing I would do is test the water. If you see any ammonia or nitrite, or if nitrate is over 20ppm, fix it with large (50%+) water changes daily. I would also up your normal water changes to around 20 to 30%>   
Thanks and best regards,
David  

Danio Problems
Hi, Thanks for your advice. I have just been out to buy testing kits and will test the water quality when I have finished work this evening, I really hope it is poor water as the TB possibility terrifies me if I'm honest. How worried should I be for my own health, I know you say that it can enter humans via open wounds but what about just being around the tank, do you know if it becomes airborne? <No, it can't. I must enter through a break in the skin>
Also, do you know of any websites that you know of where I would find pictures of Zebra Danios with TB (curved spine etc). <Here's a link to my photos in our forum. Scroll down to the next to last pic. The two female White Clouds at the top of the photo show the bend pretty well. http://wetwebfotos.com/Home?actionRequest=userview&userID=4258 Some fish become very thin, mine bloated.>
Sorry if I seem to be panicking a little! <Understood. I really try to pass along the warning without causing any undo concern. I rarely succeed. Some say the bacteria is always present in our tanks, and that it takes a drop in the fish's immune system for it to show. If true, it would seem transmission to humans is rather rare. But some very respected people here suggest sterilization of the entire system whenever TB is found. That's a hard call to make, but harder to argue against. Let's hope it's the water. Don>
Thanks again,
David

Dying Danios
Hi, We've had our tank for about 3 months now. Among the second batch of fish we got were three Zebra Danios. All three have since died, one after the other. The first one experienced a bloating and a dullness of his color a few days before dying. Both the others seemed to waste away, becoming very thin over a period of about two weeks. All refused to eat after the symptoms set in. It took all three of them about a month and a half to die total. All the other fish in the tank seem to be doing fine. Is this something that we should be concerned about either for the other fish or for ourselves, or was this just a "bad batch" of fish?
-Greg
<Hi Greg, Don here. I do think you got a batch of bad fish. The question is bad with what? They had some sort of internal infection. It could have been anything from bacteria, protozoa, even worms. Knowing what type of infection it was would set the risk to the other fish and yourself. If the Danios spines curved as they wasted away then they had fish TB, which humans can catch through breaks in the skin. I would just watch the others at this point. If any more get thin, email us back with details>
 

Hunchback Danio I am a fairly new aquarium hobbyist (1 year) and keep having a problem with "hunchback" Danios in my one of my tanks. <Not good> The tank in question is a small Eclipse Hexagonal 5 gallon with a small pebble base, plastic rock formations and a couple of small live plants that was cycled about 4 months ago. There are currently 3 Zebra Danios, a Chinese Algae Eater and many small snails (from the live plants) in the tank. My current readings are Ammonia 0, pH 7.0, Nitrite at 0 and Nitrate is 20. <Thanks for testing your water and sharing the results. But not the problem here.> I have had two other Danios run through the same symptoms as the current one, hunched back, decreased size, hover at the top of the tank, don't play with the other fish, don't eat and then finally end up as floaters that get flushed. I would like to avoid flushing anymore of the little guys if at all possible, symptoms just started a few days ago, can you help? Shelly <Hi Shelly, Don here. I saw where you posted this in our forum and strongly agree with Steve and others that this is a situation where the fish should be put down safely. The hunchback Danios have TB that can spread to humans. I know it's hard, but this is one of those times that as responsible pet owners we must act in order to keep ourselves and our other fish safe.> Humpback Danios I did not explain correctly on the bio-filter, it is a bio-wheel.  Can it be sterilized? <Yes. Soak it in a bleach solution then rinse well and soak in dechlorinator. Good to go. Boiling would also work, but may warp the wheel. Don> Shelly Humpback Danios Okay, I think I have come to the realization that I need to put my good little fish down and sterilize the tank but one more question. This tank has a bio-filter; do I need to get rid of it too? <No need to throw it away, but it must be sterilized like the tank. You will need to recycle it. Just refill it and throw in a small cocktail shrimp or a pinch of food. When both ammonia and nitrite have spiked and crashed you're good to go. Figure 3 to 6 weeks. Don> Shelly Humpback Danios Okay, I think I have come to the realization that I need to put my good little fish down and sterilize the tank but one more question. This tank has a bio-filter; do I need to get rid of it too? <No need to throw it away, but it must be sterilized like the tank. You will need to recycle it. Just refill it and throw in a small cocktail shrimp or a pinch of food. When both ammonia and nitrite have spiked and crashed you're good to go. Figure 3 to 6 weeks. Don> Shelly

I need help fast for my zebra Danio
I'm not really sure what the problem is.
<Sabrina here, to try and help>
He or she, I can't tell, has just over the past few days shown any of the listed symptoms. swollen belly, hunchback tail, head pointed upward, won't eat, but he swims normal hangs out at the top with the rest of the zebras.
<Hmm, this isn't a lot to go off.... Can you give us some more specs about your tank?  How big is the tank?  What other fish are in with the Danio?  Do you test your water for pH, ammonia, nitrite, and nitrate?  If so, can you let us know the values?  What you describe could be a number of things, but what sticks out most to me is the swollen belly - are his scales sticking out, pinecone fashion?  I'm afraid you *might* be dealing with dropsy, which is extremely difficult to cure at best, but perhaps there are other possibilities, too.  Let us know more about your tank, and we'll be more able to help you figure out what's wrong.>
Thank you for your time.
<No problem - I wish you the best.>

Zebra Danio with strange caudal fin  1/16/06
  Hello there! I've been breeding zebra Danios for a while, and recently, after my fry matured into full grown adults, I noticed that a few of them have a different colored caudal fin. All them, except these few, have the lines going through their body, go into the fin, ending when the fin stops. However, for these few, it stops where this fin is attached to the body, and on the fin, it has blotches of like black lines and black dots all mixed up on the tail randomly,  that really sticks out, and sort of reminds me of a guppies tail. I tried to take pictures so I could attach it to this, to show you what i mean, but i couldn't get the camera to focus on the Danio and everything kept coming out blurry and unfocused so you couldn't really tell what was going on. I looked all over the net but i couldn't find anything about Zebra Danios with tail fins like this, and I thought this might be something new going on, because I've never seen any other Danios like this before until now. What do
you think?
           Thanks, Tyler Ross
<Mmm, likely just part of the randomness of genetic mix... This is how the vast majority of sport mutations are "developed"... e.g. long tails... Bob Fenner>

Zebra Danios With TB  12/05/2005
Hi, We have 10 gallon tank and have started the tank 4 months from now. We bought 3 Danios to start with, and they did very well for first 2.5-3 months. We used to do weekly water change. Our local pet store suggested to not to change water for first month to have fully cycled tank. We stopped the water change. I am not sure if this is the cause or something else, but we lost our smallest fish during this time.  Rest two fishes has lived fine for some time and they started slowing down. They used to eat a lot and swim around in whole tank that is filled with natural plants. They stopped eating with that eagerness. They stopped playing. We noticed that their spine is also got curved. 
First we were thinking that they are getting old. After reading FAQ section in your website, we are scared about fish TB.  I have been touching the water to clean up the tank. Though I don't have any wounds, but still I am scared and wanted to know what measure we can take to diagnose if we got infected or not.
About the fishes, now they both are dull and during the night they lie down on the bottom of tank. Actually till light is off mostly they lie down on the bottom. If light is on, they try to swim. We can see they have hard time swimming. They most stand still at one place. I have also read on internet somewhere that when they are at the end of their life cycle, then also they develop curve in their spine. So how do I know if my fishes have TB or they are just old.
In summary these are questions I have.
1) What measures can we take to find out if we have infected ourselves with the fish TB?
< Fish TB is very very rare. If people were getting infected and it was a problem I think you would see warnings all over the place. As a precaution I just wash up after having my hands in an aquarium.>
<Rare in people, yes....  but I have seen many, many cases in fish lately - many of which were Betta splendens....  -SCF>
2) how do I find out if my fish's spine is getting curved because they are old or they have fish TB?
< More than likely your fish are getting old. Usually these little guys don't last more than a couple of years tops and the contouring of the spine is one of the signs of a fish getting older.>
3) In case of fish TB, how do I sterilize the whole tank? Do we have to start from scratch for the new fishes?
< I think you fish may have gotten ill due to poor water quality. Check the nitrates. The lower the better. These little guys like clean well oxygenated water.-Chuck>

Danio with bubble-like growth    4/3/06
Hey Crew. My zebra Danio has recently developed a small, bubble-like growth on it's bottom lip. I've had this fish for a just over a month, and this has developed perhaps within the last week or so... just after the fish was added to the main tank. I would have liked to attach a picture, but I'm sure you know how difficult it is to get a zebra Danio to sit still. The bubble is grey/clear in colour, and probably about 1mm in diameter. I'm fairly sure it's not ich, as it isn't white and has a well-defined round shape. The fish is otherwise swimming, eating, and behaving normally.
<A good clue... very likely this is "just resultant from a bump">
Here's the data on this fish's environment: 20 gal. tank with live plants, heated to 23-24c. Tankmates are two other zebra Danios, two dwarf Otos, and four Cory cats, all healthy. The tank is cycled, readings are ammonia 0, nitrite 0, nitrate approx. 15 ppm, pH stable at 8.0-8.1.
<A bit high...>
In my own research to determine what this growth is, I saw references to lip fibroma, but I only read of it occurring in angel fish. Could this be what's afflicting my Danio, or is something else afoot in my tank?
<Could be an "oma", tumorous... but doubtful here... And assuredly nothing one can treat... nor would I risk excising it. Likely will "go" of its own accord. Bob Fenner>
As always, thanks in advance for any help you can offer. JM

Wasting symptoms in Zebra Danio   3/15/06
Hello,
<Sharon>
I had a 30L freshwater BiOrb containing 3 White Cloud Minnows, 2 Zebra Danios and a living plant.
Water condition is good - Ammonia 0, Nitrates 0, Nitrites 0 and pH 7.6.
About 6 weeks ago I lost one of the Minnows. Symptoms included enlarged abdomen (I initially thought it may have been pregnant) followed by (48 hours before death) bent spine, floating near surface and lack of appetite.
In recent weeks I have noticed:
*         one of the Danios appears to be wasting away i.e. is very skinny (although it is still eating normally and active),
*         one of the Minnows appears to have an enlarged abdomen (also eating normally and active).
I lost a second Minnow last night - not the one with the enlarged abdomen. I had been away for a couple of days and returned to find it with looking skinny with a bent spine. It also had swim difficulties (probably due to bent spine), lack of appetite and was floating near surface. I quarantined it immediately in salt water, but to no avail.
I have searched your website and come to the conclusion that my fish may have either an internal parasite (bad) or TB (really bad). What do you think?
<Could be... perhaps from just "initial" troubles (you bought them with this)... But could be environmental to a large extent... or nutritional. What do you feed your fishes?>
And, if you could provide some advise for on my next course of action that would be much appreciated?
Regards,
Sharon Bell.
<Mmm, I would ask your stockist/LFS if they've been having trouble with their minnow fishes... You can/could become involved in sequential antimicrobial "trials"... in the hope of blocking something at play here. My first choice would be a Furan compound (likely Furanace). Bob Fenner>

Re: Wasting symptoms in Zebra Danio    3/17/06
Hi Bob,
<Sharon>
Thanks for the speedy reply.
<Welcome>
I just wanted to let you know that I didn't buy the fish with the BiOrb. I set the BiOrb up about 9 months ago initially (unsuccessfully) with a couple of small fancy goldfish.
<I see>
The Danios and minnows were purchased and added to the tank 3-4 months ago - after a 75% water (de-chlorinated) change, a thorough cleaning of the BiOrb and making sure that the BiOrb had cycled.
I feed them frozen daphnia, frozen bloodworms, flake food (left over from the goldfish - but I did compare the ingredients with those of the other fish foods available) and boiled peas. If I go away, I leave them a sinking pellet (Spirulina rich) to nibble on.
<Should be fine>
I do a 25% water (de-chlorinated) change fortnightly, and change my filter quarterly - whether it's dirty or not. (The Danios and minnows are much cleaner than the goldfish were!)
<Yes>
I live in Australia and haven't been able to find anything containing a furan compound.
Also, what did you mean by antimicrobial trials? And, how would I carry those out?
<Mmm... there are a goodly number of "broad spectrum, gram-negative antibiotics" sold for pet-fish use... And as hinted, the "search" for one that is efficacious here is a matter of trial/s... I would use (serially) what you can find... at a/the stock dosage of 250 mg./ten gallons system water... three times, three day intervals... with water changes between>
I will ask my LFS if they have had any trouble with their minnows this
weekend, but in the meantime is there anything else you suggest?
Regards,
Sharon.
<Mmm, the application of Epsom salt here might act as a temporary cathartic. Bob Fenner>

Minnow behaviour & health    10/3/06
Hi
<Hello there Charlotte>
I have four pairs of minnows (2 zebra Danios, 2 coldwater, 2 long fin and 2 yellow ones: apologies for the lack of description by proper name but I can't remember).
<Perhaps a small journal you can keep...>
  They all get along quite happily with four fancy goldfish and a coldwater Plec and all seem in general good health, having joined the goldfish approx 6 months' ago.
On Sunday, I purchased 3 very tiny fantails (one smaller than the zebra minnows!) and all seem well.  Today I have noticed that the yellow and long-fin minnows seem to be displaying to each other by opening their fins wide and synchronized swimming! I have been trawling the internet and my books but none give any indication as to what this behaviour means.
<Perhaps reproductive behavior... maybe just dominance displays>
Is it possible that it's due to the slightly reduced territory now there are 3 new fantails (albeit very small ones) or is it a breeding thing (one of the yellow ones looks a bit portly)?
<How large is this system?>
As a secondary point, on reading various articles relating to minnows I noticed in one of yours reference is made to a bent spine indicating TB infection.
<One possible cause of several... covered on WWM.>
This concerns me as one minnow has a very bent spine.  He's always looked like this, has grown well since purchase, as have all the other fish.  As mentioned above, all of the fish in the tank seem in general good health and water quality is fine.  Should I be concerned about TB or do I just have a minnow with a wonky back?
Your comments would be greatly appreciated.
Many thanks,
Charlotte
<Please read here: http://www.wetwebmedia.com/FWSubWebIndex/gldfshsystems.htm
You may need more room, less fish livestock. Bob Fenner>