Raising Corys on Dry Food.

[RHS788]

Sorry in advance for a long post, but I know giving information sometimes helps with answers. I have read the info here on breeding and raising corys, and searched on golden pearls...still have some questions.
I keep about 15 or so albino corys in a 29 gallon and have raised them off-and-on for years, but have sometimes had difficulty with retention rates. The fry seem to do OK for 2 or so weeks then seem to die off (sometimes, but sometimes not).
I always take the eggs and put them in a separate 2.5 gallon for starters, add some antifungus, and typically have no trouble with adequate hatches.
I do not feed BBS or Microworms, nor is it really an option for a lot of reasons. Please don't debate me on this, as I know it would be much better for the fry, but it is not going to happen.
I know these fry can be raised with dry-type foods as I have done it, sometimes with about an 80% retention rate. Sometimes not. FYI, I use an anti-fungus only until the fry are hatched.
I have tried First Bites, but with some problems. I have used the Golden Pearls, usually in the 50 to 100 micron size, and occasionally used the same in the 05 to 50 micron size. With any of these foods, I place a small amount in a teaspoon, add some of the tank water to it, then use a small dropper to place in in the bottom of the tank (bare bottom except for some java moss). I typically start off with a 2.5 gallon, after a few days move them to a 5 gallon, and after a few weeks (2 or 3) move them to a 20 gallon long for grow-out. Also, I keep 5 or so ramshorn snails in the tank to clean up any waste food, etc. I move them when I think overcrowding is a problem, or fish are dying off, which is the heart of the issue.
About the 3rd week of June I had a batch of about 100 to 200 hatch. The problem was that I was leaving on vacation for a week. I used a turkey baster, got some muck out of the filter, and added it for the newly hatched fry. I also placed some fry in the back of a Whisper filter, a trick I had used previously (successfully). Another person came in once and added some plankton flake (simply crushed it up). When I got home many were still OK. I moved them to the 20 gallon, fed them mostly the 50 to 100 micron golden pearls, and I guess I have about 50 to 60% left and they are now about 1/2 inch. I usually don't have any problems once they are that size. Matter of fact I just moved all of them to a 55 gallon tank with round gravel tonight.

Meanwhile, when I returned home, I had about 250 eggs (batch #2), which I pulled and placed in a 2.5 gallon. The fry hatched, and after a couple days I moved them to a 5 gallon bare bottom since there were so many of them. I started them off with the 50 to 100 golden pearls again, and they seemed to be doing very well for about two weeks. Maybe I would lose 5 or so a day. That increased to about 10 or more, and bottom line, I have now lost nearly all of them in the past 3 or so days (batch #2). I think the bottom of the tank was clean, and I had the snails in there to keep the food eaten.

When batch number 2 hatched, I had another 200 or so eggs (batch #3), (believe it or not). I placed them in a 2.5 gallon, thinking I finally had this figured out (as it was before I lost batch #2). They hatched and I guess I have about 150 or so now. They are about 2 weeks old, getting overcrowded so I plan to move them tonight. My concern is I will begin losing them within the next week or so in the 5 gallon (like with batch #2). I might take them straight to the 20 gallon, maybe because I had better luck with it on batch #1.
Again, sorry for the long email, but I have had the good and bad success over and over and want to improve retention rates and I need a consistent plan for success, so finally here are my questions:

1) Are any of you raising cory fry with dry food only, and if so, what are you using (including size) and how are you feeding it? I have heard that some of that type food will expand once consumed and bloats fry causing them to die. If that is true, it has not consistently been my experience.

2) Are you letting it soak before feeding, and if so for how long?

3) What fry to tank ratio do you keep for the larger harvests, and up to what size? For example if you had a 100 newly-hatched fry, what is the minimum sized tank you would keep them in once the yolk sacs are absorbed?

4) How (and do you) keep the bottom of your tanks clean? I switch between thinking I should try to keep it clean versus stuff on the bottom gives them more muck to eat? Obviously the snails leave their waste, and I try to remove it. I have tried tanks with sand on one half and the other half bare bottom as a place to apply the food. What do you do successfully?

5) Do you have any other suggestions for food without going to the live foods? Any other dry-type products that would be available? And how would you suggest feeding it?
I have tried and raised a few other types of corys, but have vowed not to seriously start until I have this down pat.
Thanks in advance for taking the time to read this and for any support.
Randy

[Corycory]

I used tetramin baby. I think it made the least problems with water quality. I fed them this for the first 4-6 weeks depending on fry size and then started on new life spectrum 0.5mm granules. They seem to grow perfectly fine on that and I had almost no losses, at least I didn't see any.
I mixed the powder food with just a bit tank water enough to soak it. Then I sucked it up with a syringe. Then I turned the syringe upside down so the food settles at the bottom and squirted any excess water out so I am left with the wet food only. Then I placed the food using the syringe in little piles around the tank over the sand, careful not to spread much in the water column as it just gets sucked in by the filters and causing water quality issues.
I'd suggest cherry shrimp for a clean up crew. They are great with cory fry and mine never touched any eggs either. They keep the substrate pretty clean for the corys but any uneaten food stays like brownish/beige fluffs on top so I just used an air line to clean up whatever I saw. I had the entire bottom covered with an inch of sand too.
As for how many cory fry in a tank, to be honest for the most part they seem to grow very fast so in 6 weeks from hatching I couldn't keep more than a cory or cory and a half per gallon of water, otherwise it gets way too crowded. Maybe it can be done with daily multiple water changes but I'd aim for plenty of room to avoid issues. I'd split them between tanks at this stage.
One needs overfiltering too and good maintenance. Also, a driftwood piece or similar décor for them to hide under and maybe some plants reduces the stress.

If you have any high amounts of deaths, improve the filtration, more water changes, less corys in a tank. Also food availability is an issue in the first couple of weeks as they need to be able to find the food and cory fry don't seem very adventurous when very small in my opinion but once they grow in a couple of weeks they start exploring everything.
Keep an eye on ammonia/nitrites and also on your Kh and possible Ph crashes as when one feeds enough it can send the stats all over the place no matter how hard you try not to.

Good luck with them. I just don't have the patience anymore.

[RHS788]

Thanks for taking time to reply. I will try the other food next time.

I think I am staying on top of water changes, but maybe not enough. What seems to work one time doesn't the next.

Thanks for the food info, I will try that next time and had not considered the cherry shrimp. Will see about that option also.

Also, what kind of sand are you using to avoid barb damage?
Randy

[Corycory]

I use normal silica sand.

[rcbows]

Just saw your Post!

I am using dry food for raising my Cory's! I use Tetra-min Flakes and First Bites dry food. I have had good luck with it! I just sprinkle the Tetra-min Flake on top of the water just like any other tank. If it gets sucked up by the filters it is trapped by the sponge and the fish feed off the sponge surface. I use 5.5 and 10 gallon tanks only for grow out and breeding. I use both a air driven sponge filter and a HOB's with a sponge prefilter that goes to the bottom of the tank and helps keep the tank clean, by providing water flow and pick up of the ditreus on the bottom of the tank. If I do water changes its using a net over the suction end of the siphon tube so I don't suck up any fry. I usually clean and water change about once per week.

The smaller batches of eggs are put into a cup with air stone doused with Methylene Blue and there water is changed daily until they hatch. I then dump them into a net breeder attached to the growout tank and treat them as the fry below. This is usually the other Cory species which I don't have as many breeders and less eggs to worry about.

I do have my breeders C. aeneus in 20 gallon longs (both Albino & Bronze) I have 10 to 20 adults in each tank. The only problem is when they spawn there are usual so many eggs, I can't put them in a cup with an air stone, if I do they end up not hatching, so I put them in a net breeder with a sponge filter underneath, douse them with methylene blue and in 3 days or so they hatch! At least the last batch did and looks like 100% hatch rate as far as I can tell. I then feed them with First Bites and 3 days later with Tetramin and one Algae wafer every other day.! After I remove the fry from my net breeder traps. I keep them in the net breeders for about a week. The net breeders attached to the side of the growout tank! When I am ready to release them into the growout tank I first sink the trap, that floats the fry, then turn it over and the fry sink to the bottom. I then do this several time to make sure all the fry are out of the trap. I keep however many the spawn was in the net breeder in that growout tank, usually with little losses but sometimes there are some! If they make it after (2) weeks I usually put (6) of them in another (10) gallon tank to clean up the excess food not eaten. Sometimes they don't make the move but most survive and I sell the rest. Most of my tanks have Cory's in them for clean up, but not all (100 Tanks) .