Our Cory similis have recently started spawning that was a nice surprise as they are still young and weren't being conditioned to breed. The first 2 spawns were taken out into a hatching tub and treated with methylene blue. We got a few fry but eggs still fungused although that could have been down to the eggs not being fertilized given inexperience of the parents (and us).
The third and biggest spawn I tried using an alder cone with water changes (as the cone did drop pH over 24hrs) for 3 days at which point all the eggs looked healthy and fertile, an improvement on the methylene blue. Unfortunatly we were away for 2 days so I removed the cone to prevent a pH crash and left the eggs to it. When we got back the majority of the eggs had fungused but the unfungused eggs hadn't hatched. Eventually 4 eggs did hatch but 6/7 days after spawning as opposed to 4 days for the first two spawns. All 4 hatches were also drawn out affairs with the fry struggling to get their heads out the eggs and actually swimming around as an egg-with-a-tail for a few hours before eventually breaking free. This contrasted with the first 2 hatches where the fry broke free from the eggs very rapidly.
As the female is very round and we've just water changed and cleaned the filter it is likely another spawning may occur so I'm now torn about how to treat any eggs. Has anyone else had issues with alder cones as the first 3 days they gave much better results than methylene blue but the delayed hatching and problems with the fry breaking out the eggs is worrying.
