# Dead fish after installing new filter



## markot (Aug 29, 2011)

I have installed a canister filter to my 20 liter aquarium 2 days ago and today I found 2 dead tetras. I checked water parameters and everything is perfect.

At the moment I'm running both internal and external filter and was planning to run both for a couple of weeks to grow bacteria in canister before I take out internal filter. I wanted to get rid of internal filter to make more space for the fish to swim and to make the tank better looking and canister is better for filtration anyway.

Now that I'm running two filters there is a lot more water flow. Could this stress fish to death?

I guess the fish died because of stress since water parameters are fine and only changed I have done is installing the filter.


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## navigator black (Jan 3, 2012)

That's a tiny aquarium for a canister. What size are you using? 
Could the fish have been pinned to the intake? A 20 L is small enough that I personally wouldn't use a motorized filter on it - that's sponge filter territory.


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## markot (Aug 29, 2011)

I'm using Tetra EX 400 filter, but I don't run it on full power. Filter specs say that it is suitable for aquariums 10-80 liters. 

I've seen fish swam around the intake and it didn't seem to move them at all. The dead ones got pinned to the intake though.


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## Hooperman42 (Oct 23, 2011)

dead small fish always tend to get stuck to it. But I run in one of my tanks (a 20 Gallon Long) two 40 gallon HOB filters. One is a bio wheel and the other stocked with Fluval bacteria little marshmallows.... the mystery snails crawl up and down the intake as do the small tetras when they go by. Id consider the stress factor. Personally your filter is fine to me if you keep the suction not so strong. My water is prestine. With an angel who had to move in due to his hostility towards another and some cherry barbs, tetras and mystery snails. and its intersting that they ALL eat some of the boiled zuchinni the snails get ever day. not that you asked. I digress....*old dude


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## Summer (Oct 3, 2011)

it does sound like a bit much for that size aquarium. I'd find a way to turn down the flow on it or cover the intake, or both


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## NeonShark666 (Dec 13, 2010)

A canister filter is too large for a 20L (4G) tank. This would cause a great deal of turbulence and may trap some fishes. A better filter would be one that hangs on the outside or an Under Gravel filter.


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