Mystery Fish Deaths..

[helenmul]

Hi Everyone, this is my first post on a forum. I have have a 210 litre tank for over six months now, I had cycled it, everything was fine, then I bought 6 neon tetras to go in, one of which looked a bit emaciated, and 90% of my fish got wiped out over a period of weeks, it was heartbreaking. The only survivors were 4 Mollies (who managed to breed in the middle of the others all dying) 3 pencil fish and a guppy. All my corydoras and clown loach were dead. On the advice of the local fish store, I bought a second 55 litre tank, moved the survivors there, and stripped the 210 litre down and cleaned in case it was a bacterial infection. Bought new Fluval 4 filter, some filter start, put dechlorinator in and did a fishless cycle. Moved the Mollies (who had bred again) back to the 210 litre tank, no deaths, fantastic. Bought a ph test kit, monitored the levels for four weeks, when nitrates were 0 PH 7.0, ammonia 0 and nitrites 0 consistently, I decided it was time to start building up my community again. Went to my LFS, chose 3 Cory catfish, one albino, one peppered and one generic, 2 plecs, as algae was starting to build up, 2 blue albino gouramis, 5 green neon tetras, 2 blue king tetras. added them to tank as specified on website, all fine for 2 days. Then got up and neons were dead. Then yesterday, the Peppered and the albino Cory were in last throes of life, unable to swim straight, turning on side, they finalyl died last night. My plecs are still going but I am fearful for them, the blue king tetras then died and this morning one of the pair of blue gouramis had died. I am gutted. What is weird is none of the fish that survived the first wipe out have died, but every time I buy new fish they dont last a week, yet there is nothing aggressive in tank. I really want to build up my aquarium again but feel like I am imposing a death sentence on them when I buy them. My kit is reading Ph 7.0, Ammonia 0, Nitrite 0 and Nitrate 0.25 this morning. I have checked this is right by taking sample to LFS and result was the same. I would welcome any advice as this is really upsetting, I love my fish and want to be able to stock my favourite Corydoras and Clown loach again but I have no idea what is wrong, why my old fish are ok- in fact thriving and breeding all the time, but yet everything new I add is dead within days..please help!!

 

[Angel Lady]

It sounds to me like the lfs where you are buying your fish from is where your problem is. When I buy fish I always keep them in the hospital tank for two weeks before I put them in with my other fish. If they are something wrong with the new fish that way they dont give the disease to my other fish..Do you have another tank you could put your new fish in for atleast two weeks before putting it in your community tank?? If so I would advice you to do this. From what you are saying it sounds like parasites mabey. Are they anything on the dead fish any sores white film or anything like that?? If so let me know so I can help you figure what is the matter..

 

[helenmul]

Thanks for replying Angel Lady..I have a 55 gallon tank which is not running at the moment. I have bought a Fluval 2 Plus for it and I did have the Mollies in it while the other one was cycling, but my hubby on an economy drive turned the heater and filter off once it was empty. I have turned it back on this afternoon, as I was begining to think the breeding mollies were attacking the new fish, although they jsut ignore the three surviving pencil fish who are thriving. Will I need to cycle the smaller tank again? The only thing I noticed about the dead fish was when the corys died, their fins were split and ragged after being fine when I bought them. I do think the mollies were attacking them once they realised that they were sick. The neon tetras were 100% intact when they died, no whitespot or anything. The only thing I can think of is some sort of parasite or internal infection but none of the long standing fish are suffering or look remotely ill. I am wondering what to do with the mollies because none of the fry seem to be dying and if they all survive I will be overrun! The blue Gourami who died seemed to be either hanging around the surface or at the bottom in the corner all the time, and his gills seemed to be clamped to his side and he was breathing a bit quick. The other blue gourami seems fine at the moment but I am very worried for him...I would welcome any advice

 

[Angel Lady]

Mollies are a very hardy fish to start with. Now do not excuse the neons for nipping they are bad for it. I have witness this first hand with the neons. They slowly ate my betta up before I caught them. As for your mollies they add up fast. And if you dont have the room for them I would suggest seperating the males from the females. Can you take the babies to the local fish store. I wont never keep mollies again they add up way to fast for me.

 

[SkiFletch]

Did you ever take readings on water chemicals (ammonia, nitrite, nitrate, pH) within a day after adding all those fish? I realize you have a very large tank there, but adding so many fish at once is not advisable. You open the tank up to disease and you open it to a mini cycle with the increased bioload. Your new fish could have gotten ammonia burn or some kind of secondary infection due to stress from adding so many at once.

When re-stocking a tank, buy and add fish slowly. A few new fish every week at the soonest, 2 weeks if you can stand waiting that long.

 

[helenmul]

I did, in fact I have been checking the levels twice a day because I have become so paranoid about the fish dying. One of my plecos has died this morning. reading 9pm last night (UK time) and 9am this morning were both Ammonia 0, Ph 7.0, Nitrite 0, Nitrate 0.25 Took a sample again to LFS to test as beginning to not believe my own readings but his were the same. I am wondering if I have a duff bottle of tap water dechlorinator, as looknig back through my diary the probs only started after a water change and adding a new brand of dechlorinator. Maybe the Mollies have become immune in some way, I jsut don't know. I am cycling my spare 55 litre tank now so I may try angels idea of quarantining new fish for two weeks first, and I can eliminate whether the mollies are carrying some strange bacteria that is killing new fish but they have developed an immunity to it. If this doesn't work I am going to seriously think about giving it up. I don't think that that was so many fish for a 3ft by 2ft by 2.5 ft tank, they looked lost in it and were only the same size as some of the molly babies who are thriving and the females are pregnant again- male is coming out as soon as 2nd tank is cycled!! Before all this kicked off I had a lovely tank with clown loach, corydoras and a good selection of tetras to build up a pacifist tank. I really miss them

 

[kat and james]

i'm so sorry to hear about your story. you just have to persevere! angel and the others have given you some really good advice, just follow it and see how you go, i know how you feel, having fish dying it isn't nice and it really does make you want to quit! we had white spot adn loads of problems after that, and we really did think about giving up, but we have survived (minus a few fish) and we are back to loving the hobby! i hope you don't give up it really is so rewarding once you come through the otherside!