Breeding

in the past, 45 years ago, i breed many different species but my favorite was kribs.
it will take a while to get a breeding pair (start with 3 kribs) but what great fun. quite small but amazingly violent fish.
in one of my 4*2*2 tanks, i had 3 very large tinfoil barbs 5 inches long 3 to 4 inches high (raised from very young) that were my favorites, a plec 14 inches long (about 3 inches when i got him) and a small breeding pair of kribs. if any of the large fish went near the eggs or fry, the kribs would beat the hell out of them it was great to watch, of course, they never done any damage to the big fish they just batter-ramed them lol.
The 2nd fav fish to breed was siamese fighters with the male working hard on the bubble nest and the 3rd fav to breed were angels which took up the majority of my 24 fry tanks in my shed, i used to swap the angels for food or plants etc to all of the fish shops, they never wanted to pay money for them lol.
i used to put a piece of glass about 3 inches wide and 15 inches long (edges arrised of course) leaning at an angle against the side of the tank. the female angel would lay eggs all along the glass with the male following her and squirting the eggs. and bred many others. with all of the spawnings, i always put an air stone under the eggs where possible even though a lot of species would fan them with their fins.
i biggest failure was with a beautiful blue lobster (that is what they were called in them days not crayfish) that hatched about 100 babies in my 6-foot tank in my shop, and even though all of my tanks had good fitting glass covers, i opened my shop one day and found all of the baby's dried up and shriveled on the shop carpet, i was gutted because i could have easily sold those lobbys, they were hard to get hold of. they had found their way out of a corner in the top that i had cut for wiring etc.
i got all of my info on how to breed from books and practical fishkeeper, there were no mobile phones or internet in those days. if you fancy breeding start with something easy like kribs, but be prepared for any other fish in the tank to get 7 bells knocked out of them. 
PS. one night we had a massive thunder storm and when i got up in the morning my 3 precious tinfoils were dead, i was devastated. apparently they are very susceptible to pressure change.

Could be any of those things Matt. Or two females…?