Why did my tropical fish die?

Question

I have kept tropical fish for a few years with no problems.All my fish were healthy until a few weeks ago i brought some new white gravel,which i rinsed well, although when i put water in my tank it did give the water a white tinge, which cleared in a few hours.I also brought a couple of new fish, from a pet shop i always use. my fish have all died gradually since, apart from 1 zebra danio. The dead fish all went a white colour, even my silver shark. (which was very big) I am gutted. was it the gravel? or maybe the new fish i got had a disease?

Answer 1

Well Lisa, based on your description, i assume you replaced your old gravel with the new white one, then added the water. My theory is that you discarded all the beneficial bacteria you had on your old gravel and did not allow your tank to properly cycle again before adding the fish again. That is definitely a no-no. Next time just mix the old gravel with the new if you plan to immediately put the fish back, and don't change all the water, but rather re-use the current water. Hope this helps

Answer 2

If the gravel came from a source outside a petshop (i.e. not suitable for aquariums) then it could have been this. However, as the fish died gradually it may well have been a disease brought in with new fish. There may have may signs before death (fin rot, white spot, fungus, lack of appetite etc).

Cloudy water (which is fine silt) from gravel can also clog the gills effectively reducing the ability to breathe. I am assuming the fish may have been in the tank when gravel was added.

If you took out the old gravel and cleaned the tank, you may also have killed the beneficial bacteria which helps clean the water, which can result in death of fishes. (The bacteria turns ammonia (dangerous) into nitrates (Safer), though check out water quality in any decent fishkeeping book for a better answer)

It may also have been a factor of both, the introduction of gravel causing stress which reduced the fishes ability to fight disease.

Sorry for the long answer as there is a variety of factors that can cause this.

Some tropical fish do turn a white colour after dying if left in water for a few hours.

Answer 3

You put too many fish in at one time. You also have fish that would out grow a 10 gal very quickly. I would start over. If you are going to do something you should research it first. A 10 gal is nice but only for a few small fish. A tank needs to be established before fully stocking it with fish. I would suggest returning the silver dollar and draining and refilling the tank. Let it sit over night and see how hot the water gets. It should be stable between 75 and 80 degrees. Then I would get 3 small fish such as guppies or danioes. Put those in for about a week feeding 1 time every other day. Then you can slowly add more fish.(2-3 small fish a week) Keep feeding only every other day for several weeks after you have added the last fish. You should only put 8 or 9 small fish total in a 10 gal tank. Then if you want to feed once a day you can, but only the amount the fish will eat in a few min. I love fish and have over 10 large tanks. If you have any other question please e-mail me. Good Luck!

Answer 4

I fully agree that if you replaced your old gravel immediately with new gravel the biological filtration went down the tubes. Especially if you cleaned the whole tank as you probably did as that would have created a huge mess. When a fish loses its colour its ammonia poisoning. So biological is my guess.
Quick question though. your silver shark. Hopefully its not a light grey with a white underside, as this shark is actually brackish not fresh, it is often sold fresh by mistake. Its a beautiful shark. I'm sorry to hear your fish died.

Answer 5

As with anything that you add to an aquarium,you have to be
cautious in your selections & pre-treatment.
I'm more than inclined to think that the new gravel is your problem.If,as you say,you THOROUGHLY rinsed it,then I can
see no reason why it would cause the water to turn milky.
It would appear to me that this gravel has been treated with
something to bleach it or with a dye to make it APPEAR white.
Had the same experience with one of my freshwater tanks &
some pieces of "white"coral that I put in the tank.
Get rid of that gravel & disinfect the tank before adding more
fish to it.
Sorry for your loss.

Answer 6

Well I highly doubt it was the gravel since you washed it so well.

I sounds like a combination of stress and possibly ich or velvet made your fish ill. Introducing new fish can be risky if they are carrying these parasites/diseases.

Did all of your fish die? are there any left?

Answer 7

I probably was the new gravel. and because some tropical fish need to be in salt water . i don;t think it was a disease

Answer 8

It was the gravel. Painted gravel has a tendency to kill fish. No matter how much your rinse it, certain brands will never be safe.

Get new, unpainted gravel and be sure you clean your tank thoroughly with hot water before getting new fish.

Sorry about your pets!

Answer 9

it could be the new white stones you bought , the stones are dyed white ,so even if you rinse the stones the dye will leek into the water /hardy fish will survive like parrot fish but fish like angels would die..... did you change the water all at once? chlorine in the water can kill your fish

Answer 10

There is a strong possibility that the gravel contained lime or another such substance. My heart goes out to you in your grief. We do love and become very attached to our animals.