canibalism and cave openings...

HI, well I have been keeping two male common Ancistrus (15 cm) and one "female, lets call her Forky" (7-8 cm) for almost a year, Forky never showed a gravid condition, also she has small non forked bristles like many females, but she has A SINGLE LONG FORKED BRISTLE!!! , all those details made me think she was just a male that didn’t mature or grow for a year, yesterday I added another "female" just the same size of Forky but this one had any bristles an looked plump so I thought she was really gravid, and today I founded the new female that I introduced yesterday really thin, so my guess is that she laid eggs but there are no eggs in the aquarium( naked aquarium with driftwood and clay caves), also Forky showed plump today for the first time in one year!!
My Hypothesis are:
The new female mated with male and layed eggs, and then the other male ate them
The importance of a small cave entrance is that male needs to stop with his head that another male gets in and eats the eggs (just like a cork)
After a female lays her eggs hormones in water stimulate other females to produce eggs in her belly
Female has anal papillae to lay eggs that looks like a tube and males don’t just like cichlids

Finally a ten gallon tank is not suitable for two males and two females, and I should take one male away from there

What do you think guys?
What is the smallest size for a female to spawn(from head to tail, no fins)?

Maybe i'm wrong, but I always thought that a 10 gallon was way to small for one BN. I'm far from an expert on these matters.

I would at the least put a male and 2 females in a 20 gallon long, but i like to use 29 gallon tanks for my trios.

The big bully try to stick his finger in my chest
Try to tell me, tell me he's the best
But I don't really give a good g@$#@*n cause
I got my lunchbox and I'm armed real well

Everytime I see "Lunchbox" I think of that lyric.

Well, the other option is that the female became stressed by her new tank and tank mates, especially in such a small tank and has re-absorbed her eggs. They can do that and it does appear that they have laid but really they have kept the nutrients from the eggs and will become gravid again when the conditions are more suited.

That would be my number one thought

Bristlenose generally dont eat eggs, they boot them out of the cave. So check filter intakes etc to see if there are some reminants stuck there. Other males will want the cave for breeding, not to eat the eggs. A new male will boot the old eggs out and promptly set about attracting a female (seen it happen )

The males do try to block the entrance, either with their tail or their head but if the conditions are right they will spawn in the oddest places. but i highly doubt they would even consider breeding in a 10G tank. Especially with more than one male in there.

After a female lays her eggs hormones in water stimulate other females to produce eggs in her belly
Female has anal papillae to lay eggs that looks like a tube and males don’t just like cichlids
What is the smallest size for a female to spawn(from head to tail, no fins)?
ehat about this?

never heard anything about the hormones, got a link to any info?

Hi guys, I've also read that if you put breeding guppies or platys in the tank with them the hormones trigger something in them to spawn.

I will try to get some abs about that

Hi everyone here is the article, its free on the web for reading http://www.biolbull.org/cgi/reprint/183/1/173

Please look at her big bristle

female with streching mark
belly view


up view

"comon male"

Well, firstly, that is one stressed male! he is very pale. altho, he has a strong looking body.

The female looks like she is gravid but again stressed, but she is def a female. I wouldn't suspect either of them would be in the mood to breed for a while.

Nice lookig shrimp in there too

Also, interesting reading in the paper. I want to get my hands on some of those other references but i'll hav to wait til i get to the library on monday for that.

in fact I stressed the male taking him out, but he has always been that colour, tha was why I thought he might be Ancistrus claro, they both live with many cleaning shrimps should I change that male for another i have like 8 more, and the others have a dark color and white tail tips always

Well, what do if i have a choice of males is put a breeding cave into the holding tank where the rest of the males are and see which ones cave up. That is probably the best indication that they are ready to breed. Then shift the cave and the male to the breeding tank. that way you have a caved male and is prefered cave in the breeding tank ready to go.

Then its a matter of waiting. The male will often leave his cave to explore the new tank but once he is happy in his surroundings he will 90% of the time go back to his cave to wait for a female. the other 10% there is usually something wrong. Usually with me i find its he had either found a better cave or I have messed up the transfur and he is stressing and in that case its all hands on deck to de-stress him asap. usually by turining the lights off, doing a water change adding water from the old tank as well as new water, darkening the room and leaving him alone to recover. once he is back to normal, if he doesnt retun to th cave i give him a week then repeat the opperation til i get some eggs.

I am in a possition where i have excessive males so i can do this no worries.

that sounds perfect to me I woll try that thank you !!

Sorry to dig up and old thread but i have been doing some more reading for my article and have found some evidence that males may in fact canabalise another males eggs after evicting him from his cave. so, keep those breeders safe

Hmmm interesting.....

I havent got any succes since that episode , the females are fat , here is rainy season i had performed regular water changes, used peat moss to lower ph, feed them with cucumber and extra protein food (cat fish food), changed males, lowered temp with water changes.
In the other hand I was absolutely shure that canibalism ocured since the preference for tight caves and the habits and adaptations of ancistrus sugest that

well, its not a sure thing. In fact, while i has been shown to happen, it is more likely that the male will keep the eggs and use them to adversite to passing females his rearing skills. it has been shown that females will prefer to breed with a male who already has eggs or even better wriggles as it shows he can care for them. also the leading theroy as to why they have bristles too