How to stop small fry from being sucked into filter inlets?

[DaveOponic]

I hope someone can suggest a good design to stop tiny fry from being sucked into the filter inlet and killed.

I found several hundred baby Tilapia in my big tank a couple of weeks ago and moved them to indoor glass tank. I have a small 40 watt water pump driving the filter but no matter how much I protect the fish from the current and the pump inlet, they still seem to be getting stuck to the surface of the fine mesh and being killed or maimed.

Does anyone have a good design for a fliter inlet system that will still clean the water but stop tiny new borns being killed.....?

Dave

[ColinW]

Hi Dave - can you show us a pic of the current filter setup?
A possible solution would be to hang the filter in a fine mesh bag that allows water to pass through - but ensure the bag cannot be sucked into the filter inlet.
eg. Cut top 1/3 of a plastic soft drink bottle that your current filter will fit hanging inside - cut or drill some holes for water to enter bottom 1/3 of bottle - slide a fine mesh Garlic bag or similar over bottle.
Best wishes - ColinW

[grassroots]

Hi Daveoponic, maybe covering it with a nylon stocking, but it might clog up to quickly. If you try it let me know how it works.
Thanks

[Ravnis]

some inevitably get sucked in it seems no matter what you do. An undergravel filter might be a good solution.

I used a flower pot turned upside down. I stuffed it with filter fiber and then put the air stone on the bottom. I used some rocks to raise the pot just a little off the bottom so water could flow up. Ok if just fry, might not be enough filtration for larger fish. I just use this till fry get big enough not to get sucked up and then turn the main filter back on.

I tried to include a sketch.

[sharky]

Hi daveoponic The reason your fry are getting sucked in is due to the suction per unit of area of your outlet. Reduce this and no problems. I suggest that on your outlet you attach a pvc pipe maybe 30cm long peppered wiicth hole. This will have the effect of spreading the 'suction' over a wider area and reducing the per area 'suction'. To be extra sure cover/wrap this 'hole-peppered pipe' with a peice of low density 0.5cm foam leaving enough to extend past the end of the pipe and tie this loose end off. You now have a pipe that is drawing its water from the entire surface/length of the foam. As a result there is very little suction at any particular point.

[hellbent]

i'd suggest using a foam filter or undergravel filter also. some people move the fry into a nursing tank which has this.