Why Oh Why Did My Little Danio Die?

[M'al-finny]

Anyone know what would cause a danio to die (float not sink after death) and would have a white lump above and behind his eyes? I found him stuck to the filter intake cover. Upon examination, he had what appeared to be his brain (or enlarged thyroid perhaps?) had burst through the skin. The skin was definitely ripped, it did not appear that something had grown THROUGH the skin.

I only had 4 danios, but there didn't seem to be excessive chasing going on. It's a 55 gal tank (hopelessly underpopulated) so they definitely had room to get away.

Has anyone ever had something similar happen? Any ideas?

 

[Leedsboi86]

I had a simlair problem with a Tetra once and it turned out he had got caught on the filter and when he struggled away he did more damage to himself then filter had done.

Could he have got stuck on filter? Or maybe another one bullied him?

 

[M'al-finny]

Yes, it very well could have been the filter. The intake is very strong and it's covered with window screen mesh. Usually the danios (being minnows) had no trouble with the current in the tank. Unfortunately, they get sucked into the first stage of the wet/dry filter frequently. Then they swim in the first intake tank until we find them and net them back to the main tank. Strong swimmers, strong enough to avoid going over the waterfall from the first intake tank (block?) into the next intake tank which feeds directly to the sump plates.

I think my filter is, like, 165 gallon running on a 55 gallon tank. (This used to be a saltwater setup, hence the overwhelming over-filtration.)

In this case, he must have gotten up against the mesh unable to pull free. Poor little guy.

Sigh. For a relatively new tank I have lost 3 fish in 3 months, all danios. Two lost to filter accidents and one to fishy TB.

 

[gourami_fan]

It could be perhaps that it died and then got stuck in the intake. Then maybe other fish started to peck at it since its dead and slowly tore away at it. Only a guess though.

 

[TylerFerretLord]

Since the apparent COD was the filter, you really should get more danios. They aren't aggresive towards each other(you made it seem that way in your post) and will school together. If you like them, get 6-10. Just not all at once!