Just a reversed-bottle-style fish catcher, sized down for multi fry...
Catching shell dweller fry can be a real challenge, unless a tank is set up with separating them in mind. But if you're like me, and you have a nicely planted and decorated tank with happy multies who are breeding like guppies, and just need to get them out to prevent massive overcrowding, it's pretty much impossible to catch the little buggers without decimating the tank. They don't run into their shells, they hide low to the ground, under the shells, behind plant roots, etc. And they can be pretty fast.
So I wasn't sure an adaptation of the simple bottle fish catcher would work if scaled down...but it does! This was my process:
First, I sourced the right size bottle. It needed to have an opening that was small enough to keep out most adult fish, and also not be too large for smaller tanks. I settled on this 8 oz squeeze water bottle from Crystal Geyser:
After pulling off the pull-top cap, I removed the screw-top lid. It conveniently has a divider to filter for really small fry, if you want. I didn't need it that small, so I clipped it out with a small pair of snips:
I then cut the top off with my bandsaw, although a pair of scissors would have been just fine:
The top part needs a small slit cut in it, so that when it is reversed and jammed back into the bottle, the edges will overlap slightly and it won't buckle. The slit is about 1/4" long:
Then, in order to promote good circulation, I punched small holes all over. Although you can melt some with a red-hot nail (heated over a candle), a narrow tip on a soldering iron or wood burner works much better. 🙂
The top jams tightly into the bottle. No sealing is necessary, making it easy to separate later. I added some micro-pellets as bait, and placed it in my tank.
After 8 hours, I pulled the bottle out; it had caught 16 fry!
Big success on the first day! Subsequent days I only caught 3 at a time, but I'll get them all eventually. Placement really matters.
I ended up making two more traps, so I can catch them faster.
Fun, quick project, useful for the breeder's toolbox!