Surrogate parent...??

In my main tank I have 3 Adult Bns (2M ,1F) an adolesent BN (F I think) a young 5cm bn (2 young to sex) and "several" (10+) baby Bns.

I know that 2M to 1 female isn't the ideal scenario but they get along fine. The older one is definately the alpha male (6" plus) and does all the breeding, the other younger male is about 4 1/2 inches.

The large male has "his" pottery cave that the younger one eyes up and sits on and the younger one has his home under a piece of bog wood.

The reason that the babies are in there is because when the BNs spawned about 6 weeks a go I didn't have roomm to move them to my other tank, so decided that when the eggs hatched the little ones woould have to fend for themselves that time.

I didn't think any had survived, however a couple of weeks later I noticed that keeping my younger male company where about 4 or 5 babies.

Since then there has been another spawn (2-3 weeks ago) , and again I left the young to fend for themselves. My young male now more than 10 young keeping him company under his piece of bogwood. The older of which now come out and eat with the the others when I put in wafers, cucumber and today blanched cabbage (Cheers for that one Parkadge). The younger newer ones don't stray too far from the safety of the bog wood.

I am pretty certain that the younger male isn't the dad as he is out from under his bogwood sitting on it, as much as he is under it and I have never seen him fanning. Also the position of the bogwood that he lives under gives quite a good view under it and Iam sure I would have seen any eggs If they were under it.

Seems that he is just looking after the young, being a surrogate dad untill they are big enough to venture out on their own. Any one else come across this sort of behaviour before..??



Jon

Hi,Maybe if you give him his own cave he might start to breed? Have you got anymore caves in there?

i have seen this a few times and it is not an unwise move by the smaller male. Females prefer to breed with males with experence and given the choice will breed with a male who already has eggs or wrigglers over one who doesnt. this is actually the main hypothesis behind the male's bristles. they look like wrigglers and trick the female into thinking he has babies and to breed with him. however, if there are a few babies rolling around then they will grab them and raise them to make it look like they have already spawned and increase their chance of breeding. In fact sub-dominant male bristlenose will raise almost anything. I know or cases where a common male has been used to fan and raise L134 fry after the dad left the cave.

How big are the fry that are living with the small male? If they are big enough to have already absorbed the egg sack the they are just hiding in the same spot as the small male. It's probable the safest shelter.