I've had a pair of fully mature blue rams for almost a year, with them being fully mature and within the past 4 or 5 months. A pair formed, and attempted their first spawning just under a month ago, and tried again, just last week. The eggs and their numbers looked healthy, and they guarded the eggs with dedication for about 48 hours. Beyond 2 days, they began to be more lax. the eggs did not hatch, and on the third day, the eggs were all eaten by the afternoon.
The pair continue to display bright colours, and I am puzzled as to why they failed the second time around. I know that usually the first batch is unsuccessful, but now it's the second batch. They spawned on an area of driftwood that they cleaned out.
My tank is a large 90 gallon, where they are the only pair of cichlids, with no others. I have only small schooling/shoaling fish in a softwater community tank. The tank is heavily planted and has adequate filtration, water movement, and parameters, with even nitrates kept very low < 10ppm.
If anyone has any insight on this please let me know - I'd appreciate it if and when they try a third time. I do not want to hatch the eggs myself because I want to encourage and preserve the brood care behavior of the specifies, and it was recommended by an article from The Fish Magazine.
pH: 6.2 to 6.4
Temp: 26C to 27C
TDS: very low to almost non-existent
Peat content: low but some dried leaves have been added in the recent past
Ammonia & nitrite: 0
Nitrate: <10 ppm
Photo of tank below with some of the small fish occupants that share the space with the pair of rams. If you look at the driftwood area in the lower middle part of the water column and to the right, that's where they breed, surrounded by narrow-leaf java fern around them.