Fish diseases...


New Member
Hello -
I'm having a rough time with my tank. I've had my 10-gallon tank set up for over a year (prior to that, an 8-gallon tank set up for 6 years) and up until a month ago I had two zebra danios, an African swimming frog and a 7-yr old Pleco. About a month ago, one of danios died - one night he seemed "bent" or distorted and was still alive, but listing. Shortly after I noticed this, he died. The rest of the tank seemed fine and about a week later I bought two new fish - an orange and a yellow molly from Petco and added a new bubble bar. I didn't quarantine them... a few days later, the yellow molly died. I assumed this was just a product of moving the fish into a new tank and he just didn't adapt to the new tank. The danio, the orange molly, the frog and the Pleco have all seemed fine for the last two weeks, although I noticed the tank was getting a little smelly. I had been giving the Pleco some extra Algae discs since lately he'd been scouring the tank feverishly. I assumed the smell was just from the extra food and I cleaned out the filter and added some new water. I did notice some pale white "strings" floating around the tank or suspended off my artificial plants. Yesterday morning I went to feed them and couldn't find the danio. I also noticed the Pleco looked like he was shedding skin or molting and his eyes were cloudy. He was alive and I was late to work so I grabbed a water sample and went off to work. On my way home I stopped at Petco and had my water tested - the kid told me my pH was way too high and the alkalinity was way up. He suggested I just do a water change and that would fix the problem. I asked him about the shedding on my Pleco and he didn't seem concerned. He did sell me some Freshwater One water, saying that the tap water (even with the AquaSafe I add) was probably causing the problem. I went home, did a partial water change, found the danio's body (also in a bent, distorted fashion), cleaned the gravel, changed the carbon filter in the water filter pump and waited. The Pleco seemed stressed but ok. The orange molly also seemed stressed and was not swimming around, but hanging near the bottom of the tank. I waited a bit for the remaining fish "dirt" to settle and went out to dinner. When I came home, the Pleco was upside down, floating near the bottom of the tank and breathing heavily. He was still shedding but now looked red and bloody. For a while he hung out upside down, then he flipped himself and floated around, then he tried to swim vertically but his tail was bent and he couldn't seem to move upwards. Eventually he swam into a corner, laid there for a while and finally died When I pulled him out and wrapped him in a paper towel, his body was a bit bloody along his lower body and tail. The orange molly and the frog both seemed ok last night, although the orange molly was still hanging out near the bottom of the tank. I stopped at Petco after work and bought a comprehensive testing kit and some more of the Freshwater One water. My ammonia level is at zero, my nitrite level is at zero, my nitrate level is around 20. The only thing that's high is the pH - it's testing out as blue as the bottom line on the chart (7.6). I tested the pH in the Freshwater One water and that was coming out exactly the same color as my tank water. In any case, I put some Liquid Neutral Regulator stuff in since that's supposed to level out the ph. I sat down to write this e-mail 15 minutes ago because my orange molly was starting to look bad - his fins were ragged and he also looked like he was shedding. Just now I went out to check the brand name of the water and found my orange molly dead now all I've got left is my lovely little frog and I really don't want to lose him too The temperature is fine, everything but the pH is fine and I'm desperately trying to bring that down with the Neutral Regulator and some water changes (I just did another after finding the orange molly).

All I can think of is that the mollies I got from Petco might have had parasites or some other disease and that infected my Pleco. The one danio died before I bought the mollies, but the two danios were at least a year old. I'm in desperate need of advice or anything so my frog doesn't go the way of the fishes...

hI there lisa..sorry to here you are having such a hard must be devastated,losing a fish that you have had for that long.I'm fairly new to fish keeping,my oldest fish is about 6 months old and if he died I would be absoulutly gutted.. ..sounds to me like your fish may have had cotton wool disease.I'm no expert but from the symptoms you have discribed that's all I can think is highly contageous and it should be treated imediatly..if you look at the top of the disease section in the forum Isabella has posted a disease chart with a list of diseases,symptoms,and what type of medication should be used for each disease.I would recommend that you look at that and maybe see for yourself the symptoms and try and match it to a disease.hopfully somone with a bit more experience will give you a more informative answer soon..sorry I couldnt be more helpfull..I hope your frog is going to be ok,I don't know if frogs can catch fish disease..?again sorry to here about your loss .. and good luck..

just a quick PS..all the information and advice I have received say that your PH is best left alone,a high PH is better for your fish than a PH that is constantly going up and down..again good luck ..
Yes, david is very right there is nothing wrong with a pH of 7.4 to 8.0 even so please do not add any more chemicals. A fluctuating pH will kill your fish much faster than one that is too high or too low. I am not saying that this had any bearing on the death of your fish as it seems that some of them died before you started to add the chemicals. It does appear or sound like they died of some sort of fungal infection and could well have been a Cotton wool disease. It is highly contagious but I have never heard of frogs getting it but the cure can be quite hard on them since it contains a chemical that can burn the skin of scaleless animals and would also have not been too pleasant for your pleco.

Treatments containing tetracyline, Furan-2, and Jungle Tank Buddies are treatments against Cotton Wool Disease.

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  • #5
HI guys... thanks for the sympathy. It was pretty devasting to lose my Pleco that I'd had for 7 years especially since he seemed to have a painful death *sniffle* thanks for the advice on the pH - I did some checking last night online regarding African dwarf frogs, and most sites seemed to indicate that frogs like a slightly higher pH anyway, so I'm not going to add any more neutralizing stuff. I stopped at Petco on my way home tonight and picked up some Jungle Tank Buddies Fungus Clear - the kid at Petco said it wouldn't hurt the frog and so far he seems ok... I'm keeping my fingers crossed. The back of the box of Fungus Clear said it clears up some of the symptoms that my fishies had, so I'm hoping that will clear up any infectious stuff lingering in the tank so I can get a new Pleco and some new danios... I'm swearing off mollies

--hmmm... I just re-read the message above... do you think the Fungus Clear is going to harm the frog or burn his skin? I probably should not take the word of some kid at Petco...
Wow Lisa, that's quite a story. I'm sorry about all of your fish , especially the pleco. How large was he? If it is a real pleco you're talking about, he was probably way too large for a 10 gallon tank. Plecos grow very large (I read up to 13-14" - but probably smaller in aquaria) and for a fish this size you want at least a 75 gallon tank.

Your water parameters are very good, and a pH of 7.6 is not bad at all. As David and Rose have said: it's better to keep the pH stable - even if it's lower or higher from what you want it to be - than to have a constantly fluctuating pH. It's rather pH fluctuations that can harm fish, not a pH that is too high or too low because a lot of fish can adapt to various pH ranges. Zebra danios are very tolerant and rather hardy fish, so it's not likely that pH killed them. Just do your water changes as usual and don't worry about pH. Adding pH adjusters (which are chemicals) to your water can bring you more trouble than relief, no matter what the people at your LFS will tell you. Besides, what is "Freshwater One water"?

It's hard to determine why your fish got sick and died because your first fish that died, died BEFORE you bought new fish. It could be that the first fish that got sick had a disease that was very contagious and even after it died the virus was still in the water and infected the remaining fish, plus the new fish that you bought. If not this, it could have been that your new fish were bought sick.

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  • #7
HI Isabella -
Thanks for all of the info. My Pleco was about 6-7 inches long I'd guess? He probably was too big for my tank and would have liked more room to move around in. If my next Pleco gets that big, I will get a bigger tank for him. The frog is still alive and seems to be just fine, so that is good. I'm still not sure how to determine if there is still a virus, bacteria or fungus in my water that would infect any new fish... after I posted my last message when I put the Fungus Clear in the tank with the frog, I started to worry about the frog, so I put my carbon filter back in the filter pump just in case the fungus clear wasn't good for the frog. I had left the carbon filter out of the tank for at least a couple hours so I'm not sure if that was enough to clear anything infectious up. I e-mailed Jungle Labs to ask about the Fungus Clear and if it was safe for frogs - the woman who e-mailed back said they haven't tested their stuff on reptiles/amphibians.. when I asked how long the Fungus Clear takes to work she said that the fungus is always in the water (?) - so I guess the Fungus Clear is just to clear the fungus off the fish? So, I'm not sure how long I should wait before getting some more danios and a pleco. Any thoughts?

Freshwater One is a brand of water they had at Petco that is supposed to be free of chlorine, minerals, etc and better for the fish than the tap water - or at least that's what the guy at Petco said. I just found it interesting that the Freshwater One water they sold me had the same pH as my tank
If I were you, I wouldn't get another pleco, unless you knew for a fact that you were going to get at least a 75 gallon tank. One 6-7" sized fish in a 10 gallon tank is something you absolutely do not want. A fish this size only suffers in such a tiny tank. Plecos need at least 75 gallons, believe me. Please don't get another pleco for your 10 gallon tank. There are many other algae eaters that are both small and effective in eating algae. Plus, they have the space to move around and they don't produce as much waste as a pleco does in a 10 gallon tank.

As for the medication you're using, I'm sorry but I know nothing about it. I suggest lots of water changes if you really want to make sure the disease is out of your tank. And if you have an additional and cycled tank, I'd suggest moving your fish there and thoroughly cleaning the infected tank. Unless you have access to a microscope and know how the virus your tank has looks like under the microscope, you can't really know if it is still present or not. The best you can do are water changes and/or a thorough disinfection of your tank.
Unsure of how long fungus clear takes to work.
Do you have a testing kit? If so, what are your ammonia, nitrate, and nitrite levels?
Most fish will not get diseases unless they are stressed, and these three waste products are the most likely stressors in any tank, though being in too small of a tank could do it, too. Frequent water changes (maybe 25% a day) while your fish are sick are usually a good idea.
You're definitely going to want to find a larger home for your pleco. I'm in the process of putting together a home for a pleco that's in the 10 gallon tank at my brother's day program. In addition to being stressful for the pleco, it's also stressful for the other fish in the tank.
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Seems like pretty good advice. pH, while important, is far less important than ammonia, nitrate, and nitrite. Ammonia is the raw waste as it comes from the fish. A small amount of ammonia will kill off a tank. There are bacteria that consume the ammonia and turn it into nitrite, which is less immediately deadly to fish, but is still pretty bad. Another type of bacteria eats the nitrite and turns it into nitrate, which is pretty mild stuff, but if in enough quantity, it will stress your fish. As their bodies fight off the damage from the nitrate, resources that would go into fighting off things like fungus and parasite infestations are in essence wasted, opening the way for these types of problems.

(By the way, the pH you listed is excellent for most fish, so there is some good news)

The most suggested test kit around here is the API master Test Kit. It seems expensive, but in the end, it does hundreds of tests for around twenty bucks, so it's worth it. The testing strips aren't good for much except for testing pH. The other tests on them are inaccurate at best, and can give you a false reading that can be dangerous to your aquarium.

Even without the kit, I'd suggest doing frequent small water changes just to be sure. A water change is always good for a tank, as long as it's done right.

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