Good news and bad news..

Hard to say for sure but I think probably not. Mbuna maternal instincts disappears pretty quickly if it manifests at all, and when it does it usually takes the form of the mother 'recalling' the fry back into her mouth at the sign of danger. I've mostly seen this occur in small 'maternity tanks' (containing just the mother and in a small tank limitiing how far the fry can venture off). In a main tank the fry typically scatter and go their separate ways.

African cichlids which do defend their fry (I've seen this once with a female msobo and all the time with my female venustus') tend to defend them fiercely, capable of driving off fish that usually dominate them. This behavior usually goes away when the fry have scattered in hiding throughout the tank or have all been eaten. Based on their level of protectiveness, any fish that could kill a protective mother in this instance would show signs of definate damage themselves (my female venustus', for example, are capable of claiming 75% of the 180gal tank, herding all other tankmates as far from her fry as possible). Usually any attempts to get past her are motivated to get the fry than to attack the mother.

A male mbuna (if the suggestion is that both parents somehow died in their defense being that there were two colbalts lost) would show no paternal instinct at all (it, like any other mbuna in the tank would consider the fry as morsels of food).

It is possible that another fish found the mother vulnerable and eliminated her for some reason (they can be weakened somewhat after the mouthbrooding period which typically includes fasting for 3 weeks or more). But that wouldn't explain the loss of the other. What's the complete inventory of fish in the 80gal tank (I see the types you have based on your signature but what are the quantities of each?)

And how long ago did the female complete her mouthbrooding (after a certain amount of days, her maternal instincts vanish as well and she'd gobble up any fry as food like any of the other fish, even though their hers).

p.s., if there is one fry in the tank there is the possibility of other survivors as well.

hey nick - just caught your post. tough break on losing those two.

I'd be with Kaybee on the breeding behaviour, and the possibility of a post-spawning female being weakened and perhaps just got picked off. The male death may be completely unrelated or perhaps he did for her and she did for him.

Seeing as how water quality is no doubt fine and you don't have any other symptoms I'd be inclined to call it one of those bad things that happen.

btw would love to see pics of your malawi set-up....that said are you wedded to the Crabros ?? on a totally different point I hate 'em

chavvies LMAO !! that sums them up

nickmcmechan said:

thanks for the great response the stocking is approx

9 yellow labs
9 blue cobalt
9 red zebra
3 honghi
4 crabro

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The losses could have been attributed to 'routine' mbuna aggression. The fish indicated in bold may be considered likely suspects. How certain are you that any of the two cobalt casualties were in fact female? With your stocklist it would seem losses as a result of male vs male would be more likely.

nickmcmechan said:

i am now wondering if i have multiple females breeding in there and there are territorial arguments going on, where the weakened females are being bullied?

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In many cases weakened females (following a mouthbrooding period) may be overly harassed or abused by males intending to spawn with her again. This is most probable when the quantity of females is low, but, based on sheer numbers, it would seem you would have to have multiple females in that group of cobalts just by the odds.

nickmcmechan said:

I've just noticed, this morning, a large female red zebra which was hiding in the rocks a lot...now its came out i've noticed its belly very swollen so its either malawi bloat or eggs?

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Probably not eggs, they usually show no indication of being full of them. A very swollen mbuna may have in internal ailment, possibly the bloat. I'd fast the tank for two days and see if there is any improvement in her condition (if the swollen belly persists after that you may have to treat for constipation or the bloat).