Making Out Like A Bandit: Spawning Corydoras metae

by JT Thomas

I like Corys, and who doesn’t, really. They’re cute, there’s a bazillion different species, they’re inoffensive, some of them will spawn at the drop of a hat, the fry aren’t too small to feed, and they’re a category 3 fish, worth 20 BAP points. Good fish all around.

I had had unlooked for success with getting C. sterbae and C. panda to breed in community tanks, and looked for success in spawning, hatching, and raising a batch of Albino C. aeneus, so I was looking for another Cory to try my hand at. Dave at Centreville aquarium had some of these come in at a pretty reasonable price, so I picked up a half dozen and added them to the 55 gallon South American community with my Albinos and Sterbas, and that’s where they stayed for about a year.

The Tanks

I set up my breeding team in a 20 long. Over an inch thick substrate of fine sand, I placed smallish rounded stones, boiled oak leaves, and some local driftwood (also boiled). The driftwood was held down with a slab of granite until waterlogged, then the granite was set upright to direct the current from the filter.

Filtration was an Emperor 400, turning over the tank volume 20 times hourly. In retrospect, I cannot recommend this technique in a shallow tank with a sand bottom (the filter eventually developed a leak and had to be scrapped, but not before fooling me into believing the tank was leaking. Grrr.) In the future, I would use air driven box or sponge filters and powerheads to agitate the surface and keep the water moving.

Initially lighting was provided by a single bulb 30" strip light, though now the tank shares a dual bulb 48" shoplight with a pair of 10 gallon tanks. A 75 watt heater was set to keep the tank at 78°F. I used my typical water, which is fairly hard Fairfax county ordinary, with a pH crash brought on by liberal use of AmQuel+ and NovAqua+ in pond concentrations. This brings general hardness down into the low single digits (leaving a bit of carbonate) and brings the PH down to about 6.0. The Oak leaves depressed this further.

For breeding real estate for whiptail catfish (this tank was set up with breeding them in mind), I put in two 6 to 8" lengths of 1 1/2" PVC pipe.

Into this, I introduced my shoal of 6 Corydoras metae, a breeding trio of Rineloricaria eigenmanni, and a shoal of 6 Gold tetras (4 of which were certainly Hemigrammus rodwayi, and 2 of which may have been something else.) Somewhere along the line, breeding populations of pond and ramshorn snails made it into the tank as well.

I used fishing line to wrap one tube in Java Moss and the other with a bit of java moss and several small java ferns.

Over time, as the Oak leaves decomposed, I started adding Java Moss to replace them, and it currently carpets about a third of the tank. (I will be collecting oak leaves to cover another third the next time I have the chance.)

Conditioning the Breeders

I treat my fish pretty well when I have time, so every evening, into the tank would go 2 or 3 spirulina tables and a couple of different types of food: a rotation of 3 days dry, 2 days frozen, 1 day live, and 1 day nothing in each week. Dry foods included 3 kinds of flake, 3 kinds of pellets, freeze dried bloodworms or tubifex, and (once I had cory fry) cyclopeze powder. Frozen is Bloodworms, Spirulina brine, Daphnia, freshwater frenzy, or mysis shrimp, typically half of a cube. Live food is blackworms and brine.

Over the months prior to breeding, I did a 30% water change weekly, using treated, aged water.

Spawning

I have never seen these cories spawn. Ever. However, while removing whiptail babies, I noticed tiny cories skittering through the leaf litter. I failed to report that at the time, but, having removed all babies from the tank, the very next time I detected free swimming cory fry, I had them checked. Apparently, the Cories deposit their eggs in the leaf litter. Subsequently, I have also seen them deposit small numbers of eggs, grouped singly, on the glass near the water line. Per planetcatfish.com, in nature, they tend to lay their eggs on the underside of the leaves of broad-leafed aquatic plants.

In order to get fry for BAP purposes, a week or so after checking, I removed all décor from the tank and using a fine mesh net and a turkey baster, moved all cory and whiptail fry to a 10 gallon tank set up for this purpose.

Raising the Fry

As I had set up a 10 gallon grow out tank for whiptail fry, I added the corys. The tank has a thin layer of sand, a scattering of oak leaf detritus, a significant amount of java moss, and floating plant coverage, initially Brazilian pennywort (Hydrocotyl brasiliensis), but later Water sprite (Ceratopteris thalictroides). This was lit by a shared 80 watt 4’ fixture, filtered by an air driven Hydro1 sponge filter, and heated to 78 (when necessary) with a 50 watt hang on filter). I fed a twice daily regimen of cyclopeze powder and microworms, or a 2:1 mix of frozen baby brine and frozen rotifers, coupled to a daily spirulina tablet. Water changes were done weekly with aged treated water. I’d squeeze the filters twice, remove all the plants and décor to a bucket with tank water (so as to not lose any fry hiding in them), and then siphon about 5 gallons (in total) of the water.

After several weeks, when the fry began to approach a quarter inch in size, I began moving them to second stage grow out tanks (typically housing some midwater fish). At this point their feeding was reduced to daily, with my typical regimen for small fish (dry food 3 times weekly, typically including flake and shrimp and spirulina pellets; frozen food twice weekly, usually bloodworms, Daphnia, or Spirulia brine; live food once weekly: Blackworms and Brine, and on Sunday they fasted.) Growth depended on the specific tanks they were in. I believe the batch I brought to a meeting for verification had spent the prior month in a 10 gallon tank with about 30 platy fry.

Conclusions

The biggest trick to spawning Bandit Cories is in the knowing that they have spawned. They scatter their eggs and typically hide them. However, with regular water changes, good food and care, they seem to be about as easy to breed as any of the easier cories.

October, 2009

Making Out Like A Bandit.
Copyright 2008 - 2009 JT Thomas

Unrestricted use of text and images by the Potomac Valley Aquarium Society (PVAS) granted. All other non-commercial use granted under Creative Commons License, so long as derivative works too are under that license.