Spawning
Spawning Grid | Spawning Mop | Feeding Fry
I am just getting back into fish keeping after quite an absence. I've had tanks running, but they are mostly just the fish leftovers. Either fish I liked too much to sell, or fish it wasn't worth trying to catch are all that I have left. I have some leftover groups and would like to enlarge their schools, but in browsing local shops the current crop of those species looks quite lackluster compared to mine. So in the next few weeks I'll be trying my hand at spawning my cherry barbs and harlequin rasboras again. I've done both before, but I always had problems feeding the fry. I'm going to try getting some live worm (nematode) cultures going this time before I breed and see if it ups my success rate.
Spawning Grid
The purpose of a spawning grid is to keep fish from eating their eggs after they spawn. Most of the schooling fish, barbs, danios, and tetras are very keen on eating their eggs once the spawning is done. In nature their eggs would be getting washed away, so they technically would likely be eating other fish eggs.
The quickest idea for a spawning grid is just plain marbles. You want two or three layers to keep the fish from digging to reach their eggs. I recently discovered a much more elegant solution.
I don't take credit for this grid design. It was described in Culturing Live Foods by Michael R. Hellweg. The basic design is a piece of light grid (plastic grid used in office buildings to diffuse fluorescent light) and a sheet of needlepoint canvas. The plastic canvas comes in different colors, dark is preferred, but I could only find white in a single piece big enough with the hole size I wanted at the place I went. It also has a few different options for hole size. The holes just need to be large enough for the eggs to fall through, but not so large the adults can follow.
You cut the light grid to a size that will fit into your spawning tank. You then trim the needlepoint canvas to the exact length and slightly wider than the inner dimensions of the tank. This will give it a tight fit. The two are held together with fishing line. I added two big loop handles of fishing line to make removing it a little easier.
Spawning Mop
This item is also useful in spawning tanks. It mimics feathery live plants, which many barbs, rainbowfish and killies prefer to spawn in. They are made by wrapping acrylic yarn around a 10-12" tall book and tying one set off. You then just cut the other end and have a bunch of pieces of yarn that are the same size tied together. You can then use the tie off piece to attach it to either a floating item, or a sinking item. Here I used bits of Styrofoam so they will float.
Soak them in hot water before using to be sure they stay colorfast.
Feeding Fry
This would be where I failed before. I'm horrible at raising baby brine shrimp, and at the time that was all I really knew I could feed to fish fry. Thanks to Culturing Live Foods by Michael R. Hellweg I'm going to try vinegar eels, microworms, walter worms, grindal worms, and maybe daphnia. The Bug Farm has more info on all of them. I'm seeing about growing infusoria as well. The only live food I currently culture is red wrigglers.
If you don't have any food ready to feed to egg laying fry you can try filter squeezings, or chunks of live plants such as Java moss in the short term. I at one point also tried something called liquifry which worked okay, but I expect not as well as worms will. Another idea is to use a mature sponge filter as the filter in a fry tank. Most sponge filtes are loaded with tiny critters fry can take advantage of.
Fry from animals like bristle nose catfish are actually easier to feed, as many of them will eat zucchini and other vegetable foods.
