You need at least 40 Litres for a pair of Bolivian rams, any second pair again 40 - 60 litres . Cardinals are great as I have 11 with my rams . Rams will get aggressive when breeding and often chase the cardinals away from any fry.
Trying to sex young rams is almost impossible , adult are much easier, don't rely on the colours as this changes depending on diet , breeding and stress. There are differences between head shape between males and females, also look at the organs, males tend to have a more pointed and angled organ pointing toward the tail fin where females is larger and more rounded ( ovipositor) . Rams don't travel well and will seem grey or washed
Out and this can last a few days until settled. I have two breeding pairs in my 125 litre and they tend to stick in their pairs. Provide plenty of cover and cave options and try to break up line of sight from one end if the tank to the other, this will limit aggression and assist when they set up territories . Great fish , loads of character they are earth eaters so a sand substrate is best . During breeding both parents will take fry in the mouth and move them to two or three different pits that they dig to protect the wrigglers before they become free swimming , this will continue as they become fry. Mine breed every 2-3 weeks like clockwork , but they take a few goes at first until they learn what to do. I have found a high quality 1mm sinking pellet
is best for feeding, with brine or bloodworm once a week.
I have found that they adapt to ph between 6-8 and temp at 25-28 c , however if you have panda cories like I have keep to the lower temp.
Great fish with amazing colours and behaviour.
