Help my fish are dying

[brattygratty]

Help!!!! I have a 20 gallon tank and had 2 black skirted tetras, 1 black neon (the other 2 died when we went away) a pleco and my betta in the tank. It was cycled and all were doing well (bought the tank and everything back in March.) Then my husband went and bought me some more fish. He bought 3 platy's 3 mollies and 3 black neons (friends for my other one). I told him it was too many and we might crash the tank, but we put them in anyway (he bought the fish at Walmart). That was on Saturday. Since them 2 of the mollies died pretty much the next day. This morning one of my platys was dead and my betta, none look sick. I tested my water levels and everything is at 0ppm. Should my nitrate levels be this low? I'm very confused I thought that there were always some nitrate in the water. Even when I tested while cycling there was atleast 5ppm nitrate. Please help I don't want any more to die.

 

[rdd1952]

Sorry to hear you are having problems and lost so many fish. You are right that it was too many fish at once. Actually, it was about too many for a 20 gallon tank period and you can really only get about 10 small 2" fish in a 20 gallon. The pleco is also very messy and will need to be moved to a larger tank soon as they will get well over a foot long.

Walmart has a terrible reputation with fish keepers. I haven't spent a cent in there since back in January when I bought 2 bettas that were in deplorable conditions. Enough about that though. More than likely the fish he got there were already sick and diseased resulting in the sudden deaths. That really wouldn't explain the betta though as you already had him. He may have been stressed by the other fish as tetras can be nippy at times, especially when they aren't kept in schools of at least 3. If anything harmed him, it would have probably been the black skirts.

The nitrate really wouldn't have been a problem although you are correct that there should be some nitrate unless you just completed a pretty big water change. Every tank, except for possibly some very heavily planted tanks, will have nitrate. My tanks generally run around 10 to 15 ppm. That is one of the reasons for water changes, to remove nitrates which can't be removed by any other method. Nitrates, as you probably know, are the end result of the nitrogen cycle. A lack of nitrate would mean that ammonia isn't being processed unless, as I said before, you have a lot of plants (or algae) that are taking the nitrate out of the water and using it.

It is odd that after introducing that many fish, you don't have any ammonia or nitrite. Are you using any chemicals other than dechlorinator that might be removing the ammonia and preventing the tank from going through a new cycle?

 

[WILDER]

Any signs of flicking and rubbing, or shaking, or twitching, red inflamed gills, or laboured breathing.

 

[brattygratty]

It is odd that after introducing that many fish, you don't have any ammonia or nitrite. Are you using any chemicals other than dechlorinator that might be removing the ammonia and preventing the tank from going through a new cycle?

I used "cycle" which is suppose to help fish adapt to new tanks. Or atleast that's what it said. It claims to reduce lag time for new nitrite and ammonia levels. As for fish behaviour, everyone seems fine, no inflamed anything, no gasping, rubbing etc. I'm not sure what the problem is. But thanks for the help. Anything would be helpful. I dont' have any plants in my aquarium, no real ones anyway. Also, my black skirts and the betta have been in the tank together for about 4 months and never had any problems. And just so I state this, my friend is taking my pleco when he gets bigger, they have a 50g tank. Another walmart sale to my husband.

 

[brattygratty]

I just did a 10% water change and now my nitrate level is at 5ppm. I think it's been about 3 weeks since my last water change, but I only had 2 black skirts, one small black neon, a betta and pleco in there before Saturday. Not sure why there is nitrate now, except maybe I did the earlier test wrong. Just to be sure I also tested ammonia and nitrite and they are still at 0ppm. Still don't know why my betta died. Any ideas on how to keep the rest alive? I don't have another tank to put them in, though we've been looking for a little while now for another "quarantine" tank. I would appreciate any help to keep the rest of my fish friends alive.

 

[modernhamlet]

Since your water parameters are solid, my best guess is that the new fish brought some sort of disease into the new tank with them. I had this happen with a group of rasboras once. They died and subsequently wiped out my original, healthy rasboras too.

Weird that none of the other fish are showing any signs of illness though.

Anyone else have any good ideas?

 

[brattygratty]

None of my other fish have died, or are even showing signs of any problems. I don't know, but am still very sad that Sammy died as a result of what was probably my own ignorance, but maybe he was just old too, who knows. Everyone else seems to be doing great now, no new dead fish today and everyone is eating and swimming around, so I'll keep an eye on it. Thanks for all the help you've all given me. My fishies appreciate it too.