Expectant?

[DaveOponic]

One of my smaller Tilapia has changed its colouration recently. It is a smaller black Tilapia and now its tail is red. (I think they are all Hybrids but most are white/pink, they all have distinctive black vertical markings the length of their bodies)

This Tilapia has taken up residence in a "cave" in the pond and is agressively chasing away any other fish that enters. It will leave the cave but only long enough to chase away any intruder.

I know Tilapia keep their fry in their mouth at some time but I don't know much about their mating, spawning behaviour.

Does this behaviour sound like a mother fish? Should I isolate her to another tank or just keep watch for signs of fry?


Dave

[DaveOponic]

A few minutes research makes me think that I have a wannabe father defending his love nest rather than a mother fish defending her eggs .....

Natural reproductive behaviour of O. niloticus
The mating system of the African cichlid fish Oreochromis spp. resembles that of other
lekking animals; males defend mating territories where the spawning pits they dig are sites
for mating and oviposition (Baerends and Baerends-van Roon, 1950; Fryer and Iles, 1972).
The female lays her eggs in the spawning pit after which they are fertilized by the male.
Under natural conditions, females may encounter solitary or aggregated males and
experience varying degrees of male interference and competition during courtship and
spawning (Nelson, 1995). After fertilization of the eggs, the female picks up the eggs in her
buccal cavity. Thereafter, the female leaves the spawning pit and rears her clutch until the
fry are free-swimming. The male continues to defend the pit and attract other females for
mating (Fryer and Iles, 1972; Rana, 1988).

Source: http://library.wur.nl/wda/dissertations/dis4088.pdf

[Jonathan Dyer]

Yeah Dave a male often changes colour when he is ready to breed and claims a part of the water.

[DaveOponic]

Big changes in the pond over the last few days. It appears there are now three males (tilapia) defending their territory in three corners of the pond. The first one (referred to in previous post) has really changed colour and is very agressively shooing away the Koi fish from his love nest while circling some of the female fish and coaxing them in.

The two other fish (I assume they are males) are not yet as colourful but their tail fins have reddened and they are defending their "pits".

Actually when I read up on Tilapia mating behaviour, I went out and bought some bags of fine aquarium gravel and dumped a bag each in their love nests.

It seems the female will lay the eggs in a pit prepared by the male who then fertilises them in the pit, later the female will scoop them up in her mouth.

No sign of any eggs or fry yet though but it is quite exciting.

Unfortunately I haven't yet expanded my system but I still have an outdoor pond being cleaned up by sucker fish. I guess the babies will have to live there until I can get some better accomodation for them.

[Hamish]

But are you going to paint the bedroom blue or pink?

[anniefish]

How about a soft green or then again bright colours are the rage for babies now. Just imagine changing (and washing) all those nappies!

[DaveOponic]

Ha ha ha! So far there is definitely one pair of fish who have made a cozy nest with the gravel. They have been busy slow dancing, tail wiggling and smooching, no eggs to report yet though. They both seem to wallow in the gravel nest intermittently. Maybe there are eggs there and I just can't see them.

The other two hopeful males are facing off at each other from their bachelor pads across opposite sides of the pond. All the eligible females are bunching up together but so far, no other matches.

The funny thing is that the Koi fish who are twice the size of the Tilapia have been pushed out of their favourite "caves" and are huddling together in a corner away from all the action.

[Jonathan Dyer]

If you do have a family in your pond the koi will eat the new fry.

[DaveOponic]

If you do have a family in your pond the koi will eat the new fry.

Jonathon,

I thought you were right with this advice but now I think that only the Tilapia ate most of the newborns. The day I noticed some microscopic fry in the tank a couple of weeks ago, I was also moving all the Tilapia to their new 1000 litre home.

In the last couple of days I have noticed there are about a dozen "survivors" happily swimming with the Koi in the pond. They have really increased in size.
From what I have read, Koi are mainly vegetarian and my Koi have shown little interest in pellets since I regularly put water hyacinth in the pond. The Tilapia also love it and eat the roots off it within days.

Dave