fish dying one by one! any suggestions appreciated

[Svetlana]

Hi,

I got 5 swordtails about 10 ago and that seems to start the problem in my tank - first all swordtails died (about one a day) including, except the new ones, also quite a grown up one that I had for about a year, then I lost 2 angels - again one a day, and now my clown loaches started to die! I lost a large ( ~22cm) one 2 days ago and another smaller one today - plus I haven't seen one of them for few days, so afraid might also be dead.

The fish left in a tank after this wipe out is 2 large clowns (that seems to be trying to avoid coming out into the open), 2 black ghosts, 2 rainbow sharks, 2 blue gouramis, 1 swordtail - all behaving quite normal - I've seen swordtail trying to scratch on the stones at the bottom of the tank, but nothing too extreme.

The symptoms: swordtails were getting very thin and hanging at the bottom of the tank before dying, angels stopped eating a day before I lost first one, the second one's stomach blow up the next day and it was dead the morning after. Clowns weren't showing any strange behaviour, except being less active/food greedy, until the last few hours before death - then the one I seen dying started to breath very fast and wasn't able to swim straight.

Any ideas of what might be the cause would be highly appreciated - I haven't lost any fish (except for swordtails) for years and now really panicking as there are no any visible signs of sickness on the fish and i really have no idea what I am up against.

Tank 450 ltr, Ammonia-0, nitrite-0, nitrate ~10. PH~7 (going without much changes for years), water changes 20-30% weekly.

[theredchaser]

Did you qt before adding your new fish?

I'm slightly confused, as you say the swordtails were getting very thin, but also mention that there are no visible signs of sickness. It takes weeks for fish to get emaciated like that so it sounds strange. What are their eating habits like?

My guess is that it is an internal disease, but also not tapeworm or parasites because they wouldn't make your angel stomach explode. When the stomach exploded, did you see any visible white strands or pieces? I haven't heard of parasites that would kill off the host in such a short time though.

My best guess is that its a bacterial intestinal infection. Standard antibiotics may help, don't know if its gram positive or negative though. I highly advise you to wear gloves when working with the aquarium just in case it turns out to be fish TB. It is a rare disease but it can be passed on to humans.

[JamieB]

Good point theredchaser, I always wear gloves when doing any task in the aquarium or changing filter media/cleaning filter unit. People do not realize how a simple soap residue or any type sunscreen residue left on hands and arms can easily kill you beloved aquatic animals.:(

[Svetlana]

Hi,

I got 5 swordtails about 10 ago and that seems to start the problem in my tank - first all swordtails died (about one a day) including, except the new ones, also quite a grown up one that I had for about a year, then I lost 2 angels - again one a day, and now my clown loaches started to die! I lost a large ( ~22cm) one 2 days ago and another smaller one today - plus I haven't seen one of them for few days, so afraid might also be dead.

The fish left in a tank after this wipe out is 2 large clowns (that seems to be trying to avoid coming out into the open), 2 black ghosts, 2 rainbow sharks, 2 blue gouramis, 1 swordtail - all behaving quite normal - I've seen swordtail trying to scratch on the stones at the bottom of the tank, but nothing too extreme.

The symptoms: swordtails were getting very thin and hanging at the bottom of the tank before dying, angels stopped eating a day before I lost first one, the second one's stomach blow up the next day and it was dead the morning after. Clowns weren't showing any strange behaviour, except being less active/food greedy, until the last few hours before death - then the one I seen dying started to breath very fast and wasn't able to swim straight.

Any ideas of what might be the cause would be highly appreciated - I haven't lost any fish (except for swordtails) for years and now really panicking as there are no any visible signs of sickness on the fish and i really have no idea what I am up against.

Tank 450 ltr, Ammonia-0, nitrite-0, nitrate ~10. PH~7 (going without much changes for years), water changes 20-30% weekly.
Hmmm...when I mentioned stomach 'blowing up' I meant getting fatter not actually exploding. And by 'no signs' I mean there was no visible creatures/substances appearing on the fish before or after death - sorry for confusion. All the dead fish I found looked like nothing was wrong with them!

Do you think bacterial intestinal infection can make them breath so fast?

From reading all over for the last few days I am more thinking about some kind of lung parasites, only assuming that getting thinner in swordtail case/ or fatter in angel case was more of a stress reaction. Both dead clowns showed no signs of either getting thinner or fatter.

I made about 30 % water change and added 1/2 tsp of salt per gallon of water to start with and will talk to LFS I bough swordtails from to see if I get any idea of what might have been wrong with them.

Unfortunately I have no place for q/t tank :(((, so just have to trust LFS when buying fish, but I haven't had any problems with fish from this shop up to now.

BTW with clown loaches and black ghosts in aquarium is it safe to increase salt dosage to 1 tsp per gallon?

[bluekrissyspike]

they should be okay but why are you treating with salt? do they have ick? or just because you don't have any other medications for them?

[Svetlana]

mainly because salt kills most of fish parasites (incl. but not limited to ich). Since the fish died quite fast without much outside signs, except for very fast breathing I assumed that some kind of gill parasites might be a problem - the good news is that I haven't lost any more fish till now!

Still trying to watch them continuously in case if any other fish will start fast breathing routine. - hope whatever attacked my aquarium is gone