Haha glad to hear it and yeah make sure your little bro doesn't get ill! If I'm honest, I've never heard of an age where its bad to breed them... I would really welcome someone to correct me if I'm wrong, but its more common for them to be "too old to breed" in its most literal sense, i.e. they physically can't produce fertile eggs any more (as a pair) though from what I've seen, a male (as in many species) can continue to breed long after a poor female has reached her fishy menopause lol, obviously there are a few things you should consider:
1) Your don't want to cause unfair stress to a creature in your care, over-breeding that results in exhaustion, excessively torn fins and any other things that could affect the health or make them more liable to infection is obviously unfair!
2) Do you have the space? For large scale breeders and those who rely on breeding as an income, the unpopular topic of culling is usually addressed, you don't want to make loads of little lives if they are going to be extinguished by you or your lack of ability to care for each of them (time, space, money etc)
3) Are you up to it? (can you be bothered)
4) Biggest question: do you need to? if you are a hobbyist breeder, you will probably be trying to make something unique, to further your line, If you do not think you have the material in this spawn to work with, try your luck! If you have enough to get one with, perhaps save the breeding for a parent with one of the better offspring. Obviously in your case you want to try for better Ventrals, so go for it! but if you are ever pushed for the requirements in (2) you have to decide whether a step backwards will help to further your breeding goals, or just waste time :)