Fish going belly up. HELP.

[Skeeter4158098]

So this is what I have a 55 gallon freshwater tank been up now for a month with a month of fishless cycle. I have a 306 fluval canister filter a 200 pro Aqueon heater 2 14" bubble bars.

Fish I have and when added

5/25
3 serpae tetras

5/30
2 serpae tetra

6/4
5 high fin black skirt tetras

6/10
5 yellow pristial tetras

6/10
5 bloodfin tetras

On 6/21 found one of my blood fins was missing couldn't find him and it was my time for my weekly water change so as I was moving things around up he floated and he was missing his head and all of his fins he had looked like he might of been a goner for awhile. The thing is he was the runt of the group when i got him from the store. So I tested my water with a api master kit and took sample to store both came back same

A.25
Ni.25
Na.40
I was told to do a 50% water change which dropped my levels to

A.0
Ni.0
Na.20-30

So they replaced my lost blood fin. And all was well till the next day when lo and behold I find one of my serpae floating side ways so it was late so could not go to the store as they had already closed.
I took the fish out and put him in a bag to take to store first thing in the morning. Which I did so they checked my levels again and were still sitting at what they were when i did the 50% water change so they replaced my serpae. So all is good I thought until today.
6/25 I couldn't find another one of my serpae thinking NO NOT AGAIN! I used my net to kind of stir my plants up and to tip my house up and what floats up? My missing serpae tetra in tack minus some fin. I am so upset I don't know what to do. When I lost the blood fin they said he must of just been not well before.
Then with the first serpae told them that I did a 50% water change and when I gravel vac I do the whole floor and was scolded for doing this saying that I'm taking to much out of the tank as far as good BB. so to find another dead serpae only a month after getting them. Are these fish all going to start going belly up a month after I get them? if so i don't know what to do. All my high fins and yellow pristilas look fine my high fins are the more agresive of the tank only to there own not so much the others.

Couple side notes on 6/23 when I replaced the first serpae I also replaced my Aqueon pro 150 heater to a Aqueon pro 200 heater and added a stand up thermometer for inside and it reads 80 as my two strips on the outside say 78-80. Reason for changing heaters was worried it was not big enough for the tank. Should I turn heater down?

 

[blert]

Being only one month old, the tank has really yet to establish so it would not surprise me to have a couple of losses. Since you have ammonia and nitrite reading you need to be keeping an eye on things daily. If you get nitrite of 0.25 or greater do a PWC, enough to get it below 0.25ppm. It really takes quite a long time (like six months) for a tank to become established and stable. If you have losses remove right away, I do fish counts multiple times a day during a fish-in cycle. Decaying carcasses in the tank will only cause big issues. Remember to only swish your filter media and not replace it with new stuff as that will only cause more cycling issues. I would not add any more fish until things have stabilized.

 

[DavidAl]

↑↑↑ ditto ↑↑↑

Your tank was not fully cycled when you began adding fish. It's not uncommon to see die-offs when you combine fish food and fish waste to a tank that has not fully cycled. I would hold-off on feeding and continue with the water changes for several days. Keep the temperature at 78°. Keep testing and see how things go. You may want to add a little aquarium salt to help counter the nitrites: 1 tsp per 20 gallons is fine.

David