Male not fertilizing eggs.... help

I have a pair of albino bristlenoses in my tank that have spawned together about 5 or 6 times now. However the last 2 spawns the male hasn't fertilized the eggs at all. He guards them, but i can tell they are not fertile then over the next day he will slowly eat them. They have produced successful spawns before and their offspring are still growing well in my tank. I just cannot understand how he is suddenly now not fertilizing the eggs? Nothing has changed in the tank at all.
Any help?
thanks in advance

How old are they?

Female is about 2-3 years id say. Male ive had from a baby so around a 1.5 years possibly. These spawns with my female are his only spawns. He fertilized them fine the couple of spawns.... just cant figure out why hes not anymore

Hi,is he in top condition? Has the temp changed? Same cave,in same place? may not be the male,could possibly be the female,are you sure of her age? is she in top conditon?

You say they have had 5 or 6 spawns,have they been one after the other without a break?

temp may have increased slightly actually its at around 27c, is that too high?... how would this affect fertilization though? yep same cave, same place. both in good condition i feed them well. im sure female is around 2.5 - 3 years old, ive also had her from a baby but cant remember when exactly i got her.

what do you mean one after the other without a break? they spawn usually every 4-5 weeks

Im sure i read somewhere that it could be the cave is too small? I dont think this is the case though because it seems big enough

If they have had spawn after spawn without a break (meaning as soon as one lot of fry are out of the cave that he has another lot of eggs more or less straight away to raise) then the male could be exhausted.He may not of had much food over the past 6 months or so and may just need a good break and a good feeding for a couple weeks.

I would turn the temp down just a touch to 26.

What do you feed them?

What size is the cave?

The being exhausted thing surely cannot be the case - he hasnt has a "successful" spawn (fertile) for a good 2.5 months so theres been no raising of fry for a long time.
have turned down temp - thanks for the advice on that

feed them mainly hikari algae wafers, they of course get fresh veggies too every week or so - courgette, cucumber, broccoli stalk etc

Cave is around 4cm wide, and 2.5cm high. about 15 cm long
here is a pic of him with his cave - it doesnt look too small does it?

cave is fine

i'd be just giving them a break for a while.

give them about a month off with no triggers then see how you go

Hi,the cave looks fine and no he will not be exhausted if he hasn't had a spawn to raise in a while.

It is difficult to say what the problem is,maybe try feeding something different like Tetra pro Veg Crisps (just a small pinch every other day) I find this a very good conditioning food.I also feed tinned green beans,you can get them in very small tins.Feeding peas once a week is a good idea too. (remove outer skins first).I would also get a couple more caves to see if he prefers a different kind.I like the clay cylindrical caves personaly.

Just a few ideas to try.There may be a medical reason or there may just be a simple reason but very hard to know really.All you can do is try a few things and maybe in a little time he may have new babies to look after.

I wish you luck and please keep us informed as to how it goes.If i think of anything else i will let you know

P.s Have they got wood in the tank?

thanks for both of your help! i will give some of those ideas a go. i was thinking about adding more caves, so i will do that.
i never trigger spawns anyway, i just feed them well and they just do it on their own haha

and yes i forgot to add that another thing that has changed (I forgot) was the addition of some driftwood about 2 months ago. im sure that hasnt got to do with the problem though.

i will definitely update next time they spawn!

Hi,the addition of the wood will of probably changed the ph and possibly gh,can you tell us your readings as it can affect the eggs if they are off the range.

hmmmmm. i dont have a gh test kit and i cant find my ph test kit at the moment but my ph is usually around 7.5 (its always been this high, and ive never had problems with breeding bristlenoses before)
if the next spawn is unsuccessful, maybe i will try taking out the wood

Bristlenoses really need wood in the tank so it's a good idea to leave it in,it may not even of changed things much.It depends on the size of the wood and the size of the tank.You really need to test the water perameters as this is the only way you can tell what is actualy happening in your tank.I definately recommend you get the water tested and post the readings.It is a good idea to test the water in the tank every so often as a matter of course.

The tank is well established so i rarely need to test unless there is a problem. the piece of wood is quite small compared to the tank though. i did just find the ph test and it came back as 7.6 like normal. its been the same for the many years i have been keeping fish.
i appreciate the advice, so thank you. I will see how the next spawn goes then update

I hope all goes well,good luck

So I changed the males cave around so it was more "private" a few weeks ago and stopped shining torches completely so I did not disturb them whatsoever.
Its been 6 weeks now and they just spawned again last night.
I checked the eggs this morning..... again ALL infertile.
Really surprised as I thought being 6 weeks since their last spawn and me completely holding off from shining torches, this spawn would be successful.

No idea what the problem could be now. Seems very odd that he produced fertile spawns from the start and now will not fertilise

Hi,are you absolutely positive of the females age?If it was me I would get another female and add her to the tank and see what happens.

Has anything been changed in the tank since they produced babies?


Bristlenoses

Yeah I am. Surely this a problem with the male though not the female?

I dont have enough room to add another bristlenose at the moment

edit: I cant think of anything that has changed at all. have bred bristlenoses in the same tank before. never had any problems

I know you say the water is fine but i would still test it to make sure.Are you positive that all of the eggs were infertile

May i ask how big the tank is and if it has lots of movement and oxygenation?



Bristlenoses

I have test kits for ammonia, nitrate and nitrite as well as ph and those are all giving me the normal readings.
Tank is 96 litres - around 3 foot long?

all the eggs are definitely infertile, they are all a creamy light yellow colour and he has started to eat them. although he is still in the cave guarding lol.

I have DIY co2 running as its a planted tank so perhaps oxygen levels could be down slightly?
I have a fluval 205 external filter on the tank. I thought this would be sufficient for movement but maybe not

Hi,everything sounds fine,nothing sounds like it could cause a problem as far as i am aware,it certainly is a bit of a mystery.The only thing you can do is try a different male or female or give them both different partners and see what happens but if you havn't got the space to do that then you are a bit stuck really.I will give it some more thought and see if i think of anything else.


Bristlenoses

thanks for all the help - I really appreciate it!
I think im going to try another type of cave just to see if that changes anything. the one I have right now is quite a tight fit. probably wont make a difference but worth a try.
other than that I guess ill just let them do their thing and hope that eventually he gets it right!

thanks again

It is worth a try,especially if he has grown some.I hope it does the trick,good luck and you are very welcome for the help,I just wish i could of helped more.Please keep us informed as to how it goes.


Bristlenoses

Yeah he has grown alot since his first spawns (which were successful!)

Will update as to how the next spawn goes probably in around 4 weeks or so

Just thought Id update since its been a long time...

So they have spawned about 3 times since updating this thread....the male is still not fertilising eggs. Even with a bigger cave. Very bizarre! I actually think he is "infertile" now. even though he has produced fry before. I dont want any more fry anyway, as i already have around 15 young plecs from his previous spawns, so maybe its a good thing! haha