Fish stuck to overflow wall.

[Covetous]

I apologize if I sound dumb, but Ive never had small fish in a drilled tank.

Has anyone ever had a problem with small fish getting sucked up against the overflow wall cuts? I have woken up to tiger barbs and rosey barbs stuck against the wall or getting sucked into the cuts and down into the sump. It only happens at night. So I don't know if they drift into it while they sleep, and then die of being stuck. Just trying to rule out possibilitys of why I'm losing my dithers at night.

 

[celebrist]

You must have a lot of flow if your tiger barbs are getting trapped against your overflow. My weirs and sump contain populations of zebra danios that have gone through but my Odessa barbs have never had any issues. Each overflow is pulling 1000 gph or more

 

[Covetous]

Well, I'm still not sure. But my pump is rated at 1650gph. Plus I have a 300gph power head in there. It's a 125g tank.

 

[Red_Man]

I had this issue with a community tank I have set up. They drift in their sleep. Set up a gopro on time lapse as I kept waking to a fish or two in the filter socks. I'm only flowing 500gph+/- through my overflows and some where able to shove off when they hit it. Some just went head first into the slots and had no chance of kicking away. I have a friend who has a 3D printer and just had him print some stand off strainers that had smaller slots and the situation was fixed. They where "L" shaped and attached below the stock slots, came out 1-1/2 inches away from the stock slots, and then where tall enough to go to the top of the tank about a 1/2 inch above the water line.

 

[duanes]

This is normal, fish often go with a flow, it's one of the ways they disperse in nature.
I have found small fish end up, (especially fry) in sumps, fluidized beds, and overflow boxes.
You can add some type of screen before the weirs to help keep them out, which also helps to keep plants out of the overflow. And the screen, doesn't necessarily need to go much below the surface.
And this sometimes gives a plenum effect which supplies a kind of dead spot to allow them to swim away, although not guaranteed.