A basic intro to the different generic classifications of Tilapia

[kellenw]

I wrote this for another forum I visit from time to time to provide some clarification on the different types of tilapia and how they breed (they were a tad bit confused). I thought it might serve some of our members (who can have tilapia) here well, so I decided to post it here also.

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When it comes to tilapia, there are mouthbrooders and substrate spawners. Within the mouthbrooding tilapia, there are several differences in terms of who (male, female or both) takes care of the eggs and fry. Tilapia are currently divided into three main generic (genus) groups according to their mode of reproduction (Tilapia, Oreochromis and Sarotherodon). This method of classification has changed numerous times throughout recent history and is still heavily debated. Making it even more confusing, hybridization between these generic groups is possible, and in some cases, somewhat common. This further muddies the waters when it comes to proper classification of the over 70 currently named tilapia species. However, here is the current situation below.

Substrate Spawners (Tilapia genus) - Males and females of the Tilapia genus build and defend the nest together. They aggressively protect the fertilized eggs and freshly hatched fry. Courtship can take up to a week in some circumstances, but a couple of days is more common. It is also fairly common for fish of the Tilapia genus to form bonded mating pairs. Tilapia Rendalli and Tilapia Zillii are the two most popular commercially grown substrate spawners.

Maternal Mouthbrooders (Oreochromis genus) - The female lays her eggs in a suitable male's pit (nest), the male then fertilizes them and the female gathers them up into her mouth (buccal cavity) to incubate for 7-10 days. The male promptly chases the female from his nest following spawning and awaits another willing female to visit his nest. Courtship is most often mere minutes, though it can occasionally last up to several hours to perhaps a day. The female does not eat any food during this 7-10 day incubation period (which is one of the primary reasons why females of the Oreochromis genus grow slower than males). She will release the fry once they are ready to swim freely. For a few more days, she will protect them, and the fry will swim back into her mouth if frightened. Some females are more inclined to protect fry after release than others. Some will simply abandon them following release and go off looking for something to eat. Oreochromis are the most widely cultured tilapia in the world. The most popular are Nile Tilapia (O. Niloticus), Blue Tilapia (O. Aureus) and Mozambique Tilapia (O. Mossambicus) in that order.

Biparental Mouthbrooders (Sarotherodon Galilaeus) - Spawning behavior is very similar to Oreochromis, except both parents will brood the eggs and defend the hatched fry.

Parental Mouthbrooders (Sarotherodon Melanotheron) - Male broods the eggs while the female leaves the nest following spawning.

[Cecil]

Good stuff Kellen! Some day I may have room for one of these species!

[DaveOponic]

Hi Kellen, thanks for posting this. I have kept Tilapia for about 4 years now. I originally bought 12 fingerlings and introduced probably 20 - 30 more "wild" Tilpaia (caught in the creeks here) into my system. From what I have read on the web, my Tilapia are hybrids of the three Oreochromis varieties. Some appear very pale, almost pink while others have definite stripes and much darker. They have very subtle jade green colouring when examined closely.

I haven't done much in the way of actively trying to breed them. For a while, I added gravel to my tanks and ponds and observed them making the nests, and agresively defending them as you have described. In fact, quite a few fought to the death. They bred without much assistance but numbers of new borns pretty quickly dwindle - quite good actually as there always seem to be enough fish to replenish the tanks.

In the last couple of weeks I have rescued a few hundred babies and put them into a small aquarium in doors. The numbers have dwindled to less than a hundred. they just seem to get stuck in the filte current and inlet. No matter how much I try to protect the pump with mesh etc, they keep dying.

Do Tilapia eat their siblings at this age??? I haven't actually seen them attacking others but notice they will eat the carcasses.

I would welcome any advice you may be able to offer on raising the fry. The biggest problem I am having is just keeping them from getting sucked into the pump. I can take out all the adults but it is impossible trying to round up and net the hundreds of fry.


Dave

[DaveOponic]

Just looking at your website, my Tilapia look a lot like your Blue Tilapia.

[kellenw]

Hi Kellen, thanks for posting this. I have kept Tilapia for about 4 years now. I originally bought 12 fingerlings and introduced probably 20 - 30 more "wild" Tilpaia (caught in the creeks here) into my system. From what I have read on the web, my Tilapia are hybrids of the three Oreochromis varieties. Some appear very pale, almost pink while others have definite stripes and much darker. They have very subtle jade green colouring when examined closely.

I haven't done much in the way of actively trying to breed them. For a while, I added gravel to my tanks and ponds and observed them making the nests, and agresively defending them as you have described. In fact, quite a few fought to the death. They bred without much assistance but numbers of new borns pretty quickly dwindle - quite good actually as there always seem to be enough fish to replenish the tanks.

In the last couple of weeks I have rescued a few hundred babies and put them into a small aquarium in doors. The numbers have dwindled to less than a hundred. they just seem to get stuck in the filte current and inlet. No matter how much I try to protect the pump with mesh etc, they keep dying.

Do Tilapia eat their siblings at this age??? I haven't actually seen them attacking others but notice they will eat the carcasses.

I would welcome any advice you may be able to offer on raising the fry. The biggest problem I am having is just keeping them from getting sucked into the pump. I can take out all the adults but it is impossible trying to round up and net the hundreds of fry.


Dave

Hi Dave,

Avoid using water pump type filters for your fry nursery tank for the very reasons you stated. All you need is an air powered sponge filter that has been "cycled" in an established tank for 3 weeks or so. This will keep ammonia and nitrite in check, but you'll still need to do partial water changes to prevent nitrate from reaching potentially toxic levels. Monitor ph, and try to keep it between 7.5-8.0. Try to keep water temps consistently between 80-82 F degrees (about 27 C degrees).

Tilapia do eat their siblings if they are small enough to even partially fit in their mouths. Young tilapia are highly cannibalistic. They will also gang up on the weaker ones and pick at them until they kill them. Nothing you can really do about that besides keeping them well fed. If well fed, cannibalistic behavior does decrease substantially. They'll still eat all the ones that die for other reasons. It's that quest for massive amounts of protein.

Let me know if you have any other questions. I'm always happy to help! :)

[kellenw]

Just looking at your website, my Tilapia look a lot like your Blue Tilapia.

Blue tilapia (O. aureus) are a very generic looking tilapia. For that matter, many tilapia look EXTREMELY similar. Blues have been used in numerous hybrid strains, so it is quite possible that they have some Blue genes in them. If I recall correctly, you are located in Indonesia. Most of the strains introduced to Indonesia have extremely strong Nile influence (O. niloticus). The most common ones being the GIFT strain, the Chitralada strain and a strain imported from Japan (the JICA). All of them are Niloticus based, and many have escaped to the wild from fish farms and river/stream cages, becoming established. For what it's worth, those are some of the pillar strains of many modern production strains. With a little selective breeding, they can be really high quality fish. Wild color Niles look a lot like wild color Blues in many ways as well.

[JoshRonin]

Hey Kellenw,

I heard in a podcast that you can breed two different types of tilapia and end up with fry that are mostly male. The host didn't say which breeds, just that it would be a great way to keep your fish from mating in your fish tanks. Was curious from an actual breeder if you've heard of this and what breeds do this? Thanks.

[kellenw]

Hey Kellenw,

I heard in a podcast that you can breed two different types of tilapia and end up with fry that are mostly male. The host didn't say which breeds, just that it would be a great way to keep your fish from mating in your fish tanks. Was curious from an actual breeder if you've heard of this and what breeds do this? Thanks.

Hi Josh,

Yes, this is possible, and there are many different crosses that will work. However, you typically need pure parent stock if you want predictable results. Even then, sometimes particular strains within a species can produce varying results. Here are some examples of various study results with different crosses.

O. macrochir male crossed to female of:
O. mossambicus - 100% male (Majumdar, 1983)
O. spilurus - 97.9% male (Majumdar, 1983)
O. niloticus - 100% male (Pruginin, 1967)

O. niloticus male crossed to female of:
O. aureus - 75-95% males (Pruginin, 1967)
O. horonorum - 75% males (Pruginin, 1967)

O. aureus male crossed to female of:
O. niloticus - 50-100% male (Lee, 1979 and Wohlfarth, 1994)... unpredictable results in several studies
O. niloticus (Stirling strain) - 100% male (Marengoni, 1998)
O. niloticus (Uganda strain) - 96-100% male (Proginin, 1975)
O. mossambicus - 100% male (Beardmore, 2001)

O. mossambicus male to female of:
O. aureus - 89% male (Pierce, 1980)

O. hornorum male to female of:
O. niloticus - 100% male (Lee, 1979 and Wohlfarth, 1990)


You can also cross many fish from the Tilapia genus with fish from the Oreochromis genus and get all males/mostly males.

[JoshRonin]

Cool thanks for that information kellen. That podcast host was saying to cross breed the fish so that you don't have them spending energy on mating, all energy could go to them growing and better food production. Nicer way to do that than using chemicals sterilize the fish. Thanks again.