[KC]

Posting on behalf of friend with no internet access currently.

Was away last weekend and when he returned lots of fish had died. He was only away Friday night to Sunday morning. 1st thought was heat, it was very warm that Saturday.

Death List:
6/9 lemon tetra
8/14 neon tetra
1/4 otto's
0/6 panda cories
0/4 GBR's
0/4 fancy tailed guppies

Did 50% water change Sunday night and fish are continuing to die. All the lemons, 4 more neons, and 2 rams. Tank is 40 gal heavily planted with a few driftwood pieces and sand bottom. Water tests currently (Thurs afternoon) show ammonia/nitrite at .5, nitrate 0. He is planning another 50% water change this evening.

None of the dead fish showed any signs of disease. No spots, no swollen bellies, good appetite, active, breathing through both gills. The guppies were added about 2 weeks prior to this along with 3 or 4 new lemon tetra. Filter pads were washed off and cleaned 3 or 4 days prior to die off along with 50% water change. I stopped by and saw his tank myself and none of the fish currently alive seem to show any signs of stress or illness. I even witnessed healthy feeding behavior.

10 or so fish died off months back when he was away over a weekend but stopped once he returned. Assumption was the heat, appartment being shut up for a day or two. But this wouldn't explain why they are continuing to die now.

Also his various swords and other SA plants have been slowly browning off recently, could this be a factor or due to very hard 250, high PH 8.2 water conditions?

Any feedback is appreciated in effort to save remaining fish and learn cause of this and see if it cant be prevented in future.

*Edit* Filter is hob rated for a 55 or 60 gal tank, can't remember which.

 

[Robin]

Sorry to hear of your friends tank.
Okay, here come the questions:

Did he do a larger than normal water change just before he left? Or any water change at all just before he left? My point in asking this is to try and determine if there is something in the water supply itself that is killing the fish.
What kind of declorinator does he use?

Was anyone in charge of feeding the fish while he was gone? Overfeeding the fish will kill them and could be the reason there is an ammonia and nitrite reading. Also if the person feeding them had any toxic substances on their fingers, (gasoline, cologne, soap, etc) this could have gotten into the tank and killed them.

How long has this tank been up and running with fish in it?

Was the tank shut off for any period of time?

My advice to your friend is to STOP feeding them for the next 12-24 hours. Check with the water company to make sure there's been no changes to the water supply and then continue to do daily or twice daily partial water changes of 25-40%. Make sure you're using a good quality declorinator--one that removes ammonia and detoxifies nitrite.
Improve water movement--(you can drop the water lever an inch so that the filter returen creates a water fall/splash)
Add salt, (sodium chloride, regular table salt without additives or aquarium salt) at the rate of 1-2 teaspoons per ten gallons to help detoxify the nitrite.

Please post back with more information

Robin

 

[KC]

Water changes were pretty much the normal, he does 50% water changes at irregular intervals (5-8 days in between). Tank has been set up and running since December in its current set up. No one fed fish while he was gone, on theory fish can go a day without food. Tank wasn't shut off as far as he knows, clocks weren't blinking due to power failure.

I told him to contact water company, he will due that at lunch tomorrow.

As for water movement I suggested adding his bubble wall wand thing to tank on Monday but fish continued dying, my 1st thought was overheating and lack of oxygen while he was away. After talking we have decided that heat was probably not the cause because he left a few windows open and let fans run in room tank is set up in now after the previous time fish died. This is close to the normal routine the tank goes through, minus the air conditioning for a few hours in the evening.

And just speculating higher temps should bother the rams less the cories but no cories died and 2 rams died after initial die off, they died on Monday and Wednesday.... Which was killer to him as the rams were center piece fish. Of the 2 pairs, 1 lost a male and the other a female. He is worried they won't pair up and isn't happy about process of getting pairs again. Rams in our area are extremely hard to find.

 

[Robin]

Okay. Doesn't sound like they were over-fed.
The ammonia and nitrite should both be 0 so that may be part or all of the problem. The daily water changes will help get them down to 0. Using a declorinator that removes ammonia and detoxifies nitrite will also help. Is he certain that all dead fish are out of the tank? A dead fish will spike the ammonia.

Another possibility here is a bacterial infection. Some of them, (Columnaris is one), can kill fish fast. Usually you will see some kind of white or grey fuzzy growth on the fish however I have read that it can be internal.

When fish die suddenly with no symptoms there's really only a few things it can be. A toxin in the water, (this would include ammonia and nitrite spikes as well as untreated water, soap residue, etc), aggression, or a bacterial infection.

As a precaution see if you can get the temp down below 80 and add salt at the rate of 1 TABLEspoon per five gallons.

How are the fish today? Eating? Gasping? Hanging at the surface or bottom or are they swimming around normally?

Robin

 

[KC]

Fish are acting normally and the deaths have stopped. Perhaps it was just due to the heat after all and it is a moderate to heavily planted tank so a fish was polluting the water? Anyways everything appears fine now and its highly unlikely it was a disease no treatment was given, no symptoms scene, and deaths have stopped.

 

[KC]

Also ammonia and nitrites are also both zero again.