Why are my tropical fish dying?

Question

There areno obvious signs of illness, no white spots, rubbing against plants, gasping, loss of colour. But about once a week for the last 6 weeks a fish dies. Just before they die they start loitering at the top of the water for a day. Once dead there are no other marks, apart from where the other fish have been eating them.

I do a 20/30% water change once a week. I've had the water tested, no obvious signs there. So far I've lost two rosy red barbs, two sunset platties, 3 tetras, two jumbo mollies... the clown loaches, corys, red tail shark are all so far okay.

The tank is 160litres. I've also lost two guppies. I have an extra air stone.

Also the tank is 6 months old. I had no deaths before this. The PH is about 7.5. I add water conditioner and bacteria growth.

Answer 1

This is a very classic sign of ammonia exposure as many other answerers have indicated. On Sunday's response I'd just like to add, you would not see this type of reaction due to nitrates, but rather ammonia. Nitrate exposure typically leaves a fish with a weakend immune system. I am thinking that this is a rather new tank? Most likely your biological filter has not been completely established, and I think this is probably combined with improper feeding habits along with over population for the tank size. With proper feeding and the proper population during an inital tank cycling out, there's a very strong chance that your ammonia levels will not reach lethal levels.

Some useful follow up info you could post for us would be, what was your ph reading before you populated the tank, what is the tank size, and how many of what kind of fish did you initally put in there. I am deducing the tank age at 6 weeks, and generally you should be clear of ammonia problems after about 4 weeks. This is leading me to believe you have not been doing any gravel cleaning or water changes, and possibly if you were doing water changes, maybe not conditioning the new water going into the tank.

Run a test on your water, and check the ammonia, nitrite, ph, and nitrate levels and post this in a follow up please.

JV

FOLLOW UP:

You definetly should not be having ammonia problems, but this is the first sign of it, the gasping for air. Take a reading on that ammonia please and see if it's showing any. Sometimes for whatever reasons, bacteria colonies can collapse and have to regrow. If ammonia is not showing, then check on your nitrites as well. Nitrites as higher levels can damge the gills. The ph is in a range where if there was ammonia, it shouldn't be lethal yet unless it's like a 2.0 or above.

Fourth answer from the bottom, though this doesn't address ammonia exposure directly, try this and see if it helps.

http://animal-world.com/encyclo/fresh/information/Diseases.htm#Diagnostic

Answer 2

It looks to me like they may not be getting enough air. Fish that are suffocating will go to the top of the tank and gasp. A good setup for a tropical tank should be at least a 10 gallon or larger equipped with a filter and a heater (keep it at about 78 or so degrees). Depending on the type of tropicals you are keeping, you may need salt as well (mostly for mollies, guppies, platys, varaitus, and swords). Also if you are overcrowded and do have a filter they will still be doing the same thing. Try getting an air pump for extra o2.
Do a good water change with a gravel siphon as ammonia will also reduce the rate at which fish can absorb oxygen from the water. At this point I would recommend a 50 percent water change as your fish are dying at a high rate. Many fish stores will test a small amount of water for you for free or you can get a test kit of your own and see what your levels are.

Answer 3

What species of fish? Could you provide any info about the tank size, and any water test results? Do you use any additives other than a water conditioner (aquarium salt, AmQuel, etc.)?

ADDITION: From the answers to my previous questions, I'd have to agree this looks like possible ammonia poisoning. If you're testing the water yourself, the chemicals you have might be out of date, or if you're using strips to test, these can be affected by moisture and how they're handled and give inaccurate results. The results may also be different depending on when you're testing the water (how close to a water change or adding the bacterial additive you use). At the very least, I'd suggest getting your store (or a different store if that's how you're testing) to confirm your results. Anything for ammonia or nitrite above 0.5 will be causing your fish stress. Nitrate should be less than 40ppm.

Another thing you need to consider is the size of your tank relative to the fish you're keeping. Even though they may have been fine in the past, your loaches and shark will probably get much larger than what they are now and they are growing - larger fish will produce more ammonia and other wastes - so your bioload is increasing, even though you aren't adding more fish.

See if your fish have shown any other of these symptoms: http://freshaquarium.about.com/cs/disease/p/ammoniapoison.htm

Answer 4

Could be most anything but sounds more like a water issue. Have you checked your ammonia levels? Get a test kit that has the basic test for an aquarium such as ammonia, ph, nitrates and nitirites.... this will help determine if the water quality is good. Make sure when you do water changes that youre adding conditioner to the new water.

Also make sure you dont have a bully in the tank. Sometimes one fish will pick on the rest and they will kill them or the fish dies of stess....

Answer 5

If the gravel got here from a source outdoors a petshop (i.e. no longer suited for aquariums) then it might desire to have been this. in spite of the incontrovertible fact that, as a results of fact the fish died gradually it might desire to correctly have been a ailment introduced in with new fish. There would have would signs and indicators in the previous death (fin rot, white spot, fungus, loss of urge for nutrients and so on). Cloudy water (this is advantageous silt) from gravel may additionally clog the gills effectively lowering the skill to respire. i'm assuming the fish would have been interior the tank while gravel grew to become into further. in case you took out the previous gravel and wiped sparkling the tank, you would be able to even have killed the advantageous micro organism which permits sparkling the water, that can consequence in death of fishes. (The micro organism turns ammonia (risky) into nitrates (safer), however check out water high quality in any respectable fishkeeping e book for a greater advantageous answer) it might even have been a element of the two, the advent of gravel inflicting rigidity which decreased the fishes skill to combat ailment. Sorry for the long answer as there's a variety of things that would reason this. some tropical fish do turn a white shade after death if left in water for some hours.

Answer 6

You are doing water changes too often and too much at a time. You will be stressing the fish enormously and that is why they're dying on you.

I do water changes once a month and only do a 10% change at a time. I use Easy Balance every week and add a general tonic when I do the water change. I've had the same fish for over a year now with very few problems.

Answer 7

There could be a number of reasons. Water temp, type of food, type of fish they are. How often do you do partial water changes? Check the chemical levels, if they get off it can cause a lot of trouble. There are any number of reasons. Call a pet store that specializes in fish, they should also do a free water test for you and let you know if they find any problems. It could be the type of fish you have. Tropical covers a lot of area.

Answer 8

It sounds like it's most likely something in the water. Be sure you're using a good conditioner with each water change and you're rinsing the filter and adding bacterial supplement weekly. This will keep the water in good condition. Change half the water at the most first off, and then change the water weekly for a few weeks.

Answer 9

Try giving them extra food, give them as much as they will eat so they is none left after feeding, keep increasing until they start leaving some then u will have established a satisfactory level as the dominant fish will eat the lesser fishes share.
Also try installing an air curtain

Answer 10

You may want to replace the food. Check for high nitrates over 40 ppm is suspect. When in doubt stop feeding and start changing water. Fish should not be dying.