Fish died in the tank: What do I have to do to prepare the tank for a new fish?

I would just replace the water and the filter cartridge and run the filter for a few days before adding any new fish.You could probably get away with just a new filter cartridge. I had real plants in my tank so it wasn’t a big deal when a fish died. Do you have a heater in the tank?

@Adirondackwannabe: Yes, but I took it out for the summer. It’s not in the tank now.

@jca I never took mine out. I didn’t want any temperature fluctuation at all.

From personal experience, I clean the tank with soap and water. Lay out the gravel and artificial plants in a design that I would enjoy looking at. If its a small tank, my advise is to keep the plants in just one corner where the fish could hide and the rest of the space open with just well placed small rocks here and there to give it a natural look.

This open space is also so you could see your fish swim and enjoy it.

I then slowly fill it with water and then treat it with the proper chemical to get rid of chlorine that kills fish. I then put the filter and light apparatus. And now its ready for the fish!

Ok, not to totally geek out or anything, but here’s the deal with fish tanks.

Firstly, your city puts chemicals in the water that are deadly to fish. In some cities it is just chlorine. In other cities like Austin, for example, they have started putting a chemical that leaves behind ammonia, which is also deadly to fish, so just letting it sit doesn’t do the trick. In any case, you can get drops at your local fish store that will remove chlorine.

The next thing you need to know about is the whole Ammonia->Nitrite->Nitrate cycle. Fish excrete waste in the water, which is high in ammonia and deadly to the fish. There is a bacteria that converts this ammonia into nitrites and then there is another bacteria that converts the nitrites to nitrates. So… what you really want to do is promote a healthy eco-system in your tank rather than just starting over.

Remove the dead critter, change your filter cartridge, do a ½ tank water change, put in chlorine drops, and let the tank circulate for a couple of days. The new water will dilute any excess nitrates in the old tank and the old water will retain enough bacteria to deal with the waste from the new fish when they go in. You should be good to go from there.

I use Poland Spring.

@jca That’s probably good. If you ever try real plants you’ll probably need an iron supplement. Our water here is low in that and plants died without it.

Clean the tank with a biological type soap like green clean (Home Depot) that isn’t chemical based and let everything dry, use filtered water to re fill it and use a bowl prep tablet to correct the ph and make sure any harmful residue is gone.

I have read that vinegar is a good cleaning agent which is safe to use in fish tanks. I tried it a few days ago, and my fish is fine in the tank I cleaned with vinegar.

Have you tried asking uberbatman? He knows a lot about fish.

I would be concerned with using any kind of cleaning agent in the tank in case there is residue that remains after. Clean water and a brush for the glass. Sometimes I will clean the plastic plants from time to time in a container that has a little clorox in it mixed with the water. Cleans them like new but there is a long rinsing process I use to be sure all the clorox is completely gone. The plants come out looking brand new after a few days sitting in clear water, swish areound and dump out the water and put clean water back in and let it sit for another day, or so. Sounds like overkill but I have yet to have any negative reactions from it. I keep an extra set of plants and rotate them so I have a pristine set ready to go.
I use “Aquasafe” from Tetra to condition the new water, and a dash of “Nitraban” from the same company to extend the usefulness of the water change.

Too bad about your fish but it happens to all of us every now and then.