tl;dr: I got wrigglers, details below.
Tank: 75 gallon community: Cardinal Tetras, Angels which just spawned, German Blue Rams which just spawned (unsuccessfully - the Ivans ate the egss), Bushynose Plecos. Buffered substrate (generic version of Akadama), moderately planted (lots of Amazon Swords, Crypts, Valls), 64 watts 6500K lighting. Ivans came from guest speaker in the local fish club, purchased together (6) when they were half an inch long. The largest male and female paired off about 2 months ago, and were removed to a 10 gallon tank. They did absolutely nothing in this tank, and started to look stressed (male is about 4" female 3", so it's no surprise in such a small tank), so back in the community tank they went. This was about a week ago, didn't record it in the tank log.
pH 6.2, 82 F, GH 5, KH <2, TDS 160. 15% water change with cold water triggered spawning, which took around 90 minutes. Approximately 150 eggs were laid on the inside of a 4" diameter clay flower pot. 125 of those were removed 2 hours after spawning to other tanks. All the eggs in the main tank had turned white 48 hours later. Of the eggs that were removed, 100 went to a 10 gallon (fully cycled; same parameters, substrate as community tank) tank with a sponge filter and a dozen Painted Fire Red shrimplets (in theory, to control fungus growth on the eggs similar to how the corydoras and killifish people do things). All of these eggs seem to have fungused (posting this exactly 4 days after spawning), but I haven't given up hope yet.
The remaining 25 eggs were placed in a 1 gallon bowl with RO water and 2 shrimplets. The shrimplets were a mistake, they immediately died and had to be removed. A 50% water change was done daily (with RO water), bowl kept at room temperature with a sponge filter (uncycled) (no AC, temp probably high 70's). Around half of these eggs hatched today, and are now wrigglers. I plan to feed microworms once they're free swimming, as hatching BBS twice a day is far too much work.
For anyone else doing this, I'd be interested to see the hatch rate with methylene blue, or possibly methylene blue + shrimplets. I think the big reason the shrimplet method failed was because there was enough algae in the tank that the shrimps prioritized it over keeping the eggs clean. I'd recommend introducing the eggs into an established shrimplet colony. Perhaps a crystal red colony would work well, as their water is already spotless, assuming the eggs will hatch at a cooler temperature. I'd also consider removing all the eggs and separating the parents next time. They just aren't as good parents as my Apistogramma cacatuoides. I recommend splitting the eggs 3 ways: 50% to a bare bottom tank with RO water, 25% to an established shrimp colony, and 25% to a bare bottom tank with methylene blue. Please, please post your results somewhere so I can have better luck next time. I don't usually post spawning reports like this, but there's so little information available on Ivans that I felt this was warranted.
I'm posting this to a couple other forums, and I'll try to edit this post to answer questions as best I can.
Tank: 75 gallon community: Cardinal Tetras, Angels which just spawned, German Blue Rams which just spawned (unsuccessfully - the Ivans ate the egss), Bushynose Plecos. Buffered substrate (generic version of Akadama), moderately planted (lots of Amazon Swords, Crypts, Valls), 64 watts 6500K lighting. Ivans came from guest speaker in the local fish club, purchased together (6) when they were half an inch long. The largest male and female paired off about 2 months ago, and were removed to a 10 gallon tank. They did absolutely nothing in this tank, and started to look stressed (male is about 4" female 3", so it's no surprise in such a small tank), so back in the community tank they went. This was about a week ago, didn't record it in the tank log.
pH 6.2, 82 F, GH 5, KH <2, TDS 160. 15% water change with cold water triggered spawning, which took around 90 minutes. Approximately 150 eggs were laid on the inside of a 4" diameter clay flower pot. 125 of those were removed 2 hours after spawning to other tanks. All the eggs in the main tank had turned white 48 hours later. Of the eggs that were removed, 100 went to a 10 gallon (fully cycled; same parameters, substrate as community tank) tank with a sponge filter and a dozen Painted Fire Red shrimplets (in theory, to control fungus growth on the eggs similar to how the corydoras and killifish people do things). All of these eggs seem to have fungused (posting this exactly 4 days after spawning), but I haven't given up hope yet.
The remaining 25 eggs were placed in a 1 gallon bowl with RO water and 2 shrimplets. The shrimplets were a mistake, they immediately died and had to be removed. A 50% water change was done daily (with RO water), bowl kept at room temperature with a sponge filter (uncycled) (no AC, temp probably high 70's). Around half of these eggs hatched today, and are now wrigglers. I plan to feed microworms once they're free swimming, as hatching BBS twice a day is far too much work.
For anyone else doing this, I'd be interested to see the hatch rate with methylene blue, or possibly methylene blue + shrimplets. I think the big reason the shrimplet method failed was because there was enough algae in the tank that the shrimps prioritized it over keeping the eggs clean. I'd recommend introducing the eggs into an established shrimplet colony. Perhaps a crystal red colony would work well, as their water is already spotless, assuming the eggs will hatch at a cooler temperature. I'd also consider removing all the eggs and separating the parents next time. They just aren't as good parents as my Apistogramma cacatuoides. I recommend splitting the eggs 3 ways: 50% to a bare bottom tank with RO water, 25% to an established shrimp colony, and 25% to a bare bottom tank with methylene blue. Please, please post your results somewhere so I can have better luck next time. I don't usually post spawning reports like this, but there's so little information available on Ivans that I felt this was warranted.
I'm posting this to a couple other forums, and I'll try to edit this post to answer questions as best I can.