Spawning Report: Corydoras adolfoi (Adolfo's Cory)

Corydoras adolfoi (Adolfo’s Cory) Spawning Report

Submitted by Patchin Crandall Curtis

Background: I purchased 9 very small tank-raised Adolfo Corys from Batfish Aquatics in January and February 2015. I raised these up, and in 2016 had a very successful breeding colony that ultimately grew to about 60 fish. In preparation for a 6 month trip to Paris, I rehomed all the Adolfos except for 13 babies which were kept in a 180g community tank while I was gone. Upon returning in June, 2017 these had grown into large, healthy sub-adults although they had not yet reached sexual maturity. They kept growing into beautiful adult fish.

Then disaster struck in August 2018 as I was bringing the fish room tanks back online for breeding projects. A ceramic dish of Repashy that had been attached to the side of the 180 g tank was knocked down and turned upside down on the substrate where it stayed until I noticed it a couple of days later. Underneath it, an anoxic colony of harmful bacterial grew below the surface. A couple of Adolfos developed white fuzz on their barbels. One had a significantly eroded mouth, and I immediately moved it to a hospital tank where it healed nicely although its barbels have never returned. The rest were treated with a fungicide in place. I did several consecutive, thorough siphonings of the substrate and turned it over every few days until I was positive there was no more anoxic bacteria growing. The health of the population stabilized and they thrived again.

Then a different disaster struck. As part of the breeding program, I wanted to perform an outcross between my tank-raised and wild-caught Adolfos which I had been trying to source for a few years. Suddenly, wild-caught Adolfos became available. In May 2018, I purchased 10 WC Adolfos from The Wet Spot and 6 WC Diamond Tetras. The tetras were noticeably affected by a parasite which I erroneously diagnosed as ich. I was short on quarantine tanks, so I put the Diamond Tetras in the same tank with the Adolfos thinking I could simply treat it for 5 days for Ich and all would be well.

This was a stupid and, as it turned out, disastrous decision. The Diamond Tetras were actually most likely infected with Epistylis, a parasite which attaches to the outside of the fish causing irritation and excessive production of slime coat which serves to protect the parasite from medications. To treat epistylis, I should have immediately given the tetras a salt dip to remove the slime coat and then medicate them. The consequences of this bad decision were that all of the diamond tetras and Adolfo Corys died horrible deaths over the course of the next two months despite trying many different courses of medication. All equipment for that tank had to be isolated and regularly disinfected. In the end, after the last fish died, I put a full tablespoon of potassium permanganate into the 20 gallon tank and walked away from it for a month in despair.

In the meantime, I had purchased another 5 WC Corydoras adolfoi from The Wet Spot and put them in a quarantine tank by themselves. They got weaker and weaker and began to die. I froze one for a necropsy. In September, Barbie Fiorentino came to stay with me and evaluated my ailing Adolfo population and suggested that they were probably suffering from a parasite called Oodinium. Using CCA’s microscope, we performed a necropsy on both a purchased TR and the purchased WC Adolfo Corys and found Oodinium in both. The WC had almost no gill tissue left at all. Barbie recommended using ProForm-C, a combination formalin-malachite green medication that is very effective against a broad range of parasites.

Determined to heal the purchased tank-raised Adolfos and to take one more pass at WC fish, on 9/12/2017 once again I purchased 10 WC Corydoras adolfoi from The Wet Spot. I performed a 15 day course of ProForm-C (3 days on, 3 days off, 3 days on, 3 days off, 3 days on) with large water changes 24 hours after each application of the medication. 4 fish died during this process but at the end I had 6 healthy, bullet-proof WC Adolfos to use as the foundation of my new breeding program. Those fish then spent a full 6 months in quarantine.

I share all this drama to help others avoid making the same mistakes I did.

At long last – success:

Upon conclusion of the 6 month quarantine, in January 2019 I moved the TR and WC fish into a 38 gallon tank with a substrate of CaribSea Peace River gravel and planted with Bacopa caroliniana and Amazon Chain Sword. In addition, I placed a piece of Malaysian driftwood with Christmas moss wrapped around it in the tank. The tank has a mattenfilter for filtration and is heated to 78o F. 50% water changes were performed weekly. In contrast to many other species of Corydoras, Adolfos prefer warm water changes (80-82o water), not cool water changes. The water was soft, neutral, charcoal-filtered tap water. The tank was fairly regularly fertilized to feed the plants which grew rapidly. After water changes, sometimes I remembered to add SeaChem or Tetra Blackwater Extract which the fish adore. Nothing gets them to turn on their orange spots and dance around like some tannins.

The fish were conditioned for spawning using Repashy Igapo Explorer mixed with 25% Repashy Redrum, Xtreme Catfish pellet food, live blackworms, and frozen blood worms. At least 4 of the WC fish proved to be females. It can be hard to sex Adolfos because they are not very fecund. Females usually only lay 2-6 eggs per day. Sometimes you can tell when they’re gravid, but not always.

On February 18-19, a series of large storms rolled through the region, so I performed an extra-large water change, and the colony went into action. In 24 hours there were about 36 eggs placed on the glass, under the leaves of plants, and in the Christmas moss. All the eggs appeared to hatch in 36-48 hours. None developed fungus.

I never saw any larval fish, but about 3 weeks later I noticed something really tiny scoot when I was cleaning the tank. Then a few days later, it seemed like multiple tiny things would scoot, but they were so fast and tiny I couldn’t focus on them. It took about 3-4 weeks before the babies would emerge from the Christmas moss long enough for me to get a look at them. At that size, they still retained their brown speckles. At 4-5 weeks, the speckles faded and they began to assume their adult coloration of a pearly white base with dramatic black dorsal stripes and eye masks with the characteristic orange spot on top.

Meanwhile, the adult fish were continuing to regularly lay eggs, and they all seemed to be hatching. No eggs have ever been removed from the tank. I never saw an adult eat any of the eggs. It’s entirely possible that some, or even many, of the larval fish have been eaten by adults as they hatched, but none that I have witnessed. What is clear is that as of 6/23/2019 there are must be 40-60 youngsters (possibly many more) of varying sizes in the tank.

The baby Adolfos show absolutely no fear of the adults from the time they are even a few mm long. If something disturbs them, they will dash right under the belly of the nearest adult fish. One of my preferred techniques to raise Corydoras babies without risking water quality issues is to feed them Repashy food (Igapo Explorer, Soilent Green, or Spawn ‘n Grow) served on ceramic disks placed on the bottom of the tank. Even the tiniest babies quickly recognize the ceramic disks as feeding stations and come running at chow time. This way, you can be sure that the babies are finding the food, and there is no uneaten food lurking in the substrate that then requires siphoning out. I learned this from watching a video on Repashy food by Ted Judy, and it has proven to be invaluable advice.

The tank has become ridiculously overgrown with plants, overcrowded with fish, and populated by an appalling number of pond snails. It also requires a really good siphoning of the gravel underneath the driftwood. I’ve been afraid of disturbing the tank too much for fear of inadvertently killing babies, but it’s time to do a thorough cleaning and to start removing a bunch of the larger juveniles into a grow-out tank. Yikes. I’ll wait until tomorrow to undertake that project. How to catch those tiny, lightning-fast babies…