Reef Discussion

Dr. Schell

The Fuckin' Doc
Jul 12, 2011
1,972
1,228
Brisbane
DIY artificial incubator for Mouthbrooding species (making an egg-tumbler)
One of the problems faced in artifically incubating the eggs of mouth-brooding species (eg. Cardinal Fish, some freshwater cichlids) is how to provide a constant, yet gentle flow of oxygenated water to the eggs to keep them in constant movement. One method of achieving this is to create what is referred to as an egg tumbler (pictured below).

To create an egg tumbler, I use a 600mL plastic soft drink bottle. I cut out the bottom of the bottle and insert a coarse foam insert and push it all the way to the top of the bottle. Next, I get a plastic tube and insert it onto the top of the bottle and into this I put an airhose so that it is touching the foam insert in the bottle. Finally, I cut out another piece of coarse foam, strech a piece of stocking over it (on the top side) and then place this in the bottom of the bottle. This eill then form a cavity in the bottle, the bottom of which is lined with the fine stocking. To insert the eggs, simple remove the bottom "foam plug" and once they are inside, replace the "plug".

Once inside this set up, the eggs are secure from preditor and the incubator will not take up too much room in the display tank. Once the eggs are inside, start the airpump so that bubbles flow out of the top tube. This will cause water to be drawn up through the bottom sponge, and well result in the eggs being in constant motion.

To add to the ease of instalation, you can add suction cups as needed.

Artificial Cardinal fish egg incubation.JPG
 

MagicJ

Moderator
Jul 11, 2011
9,650
3,761
Hobart, Tasmania
They look so cute :p

I have read other accounts of raising bangai's where they have used an artificial urchin - apparently in the wild the bangai babies obtain protection within the spines.
 

Dr. Schell

The Fuckin' Doc
Jul 12, 2011
1,972
1,228
Brisbane
Yes, the colouration of the cardinals (black vertical bands) has evolved to blend in with the spines of diadema urchins
 

marineclass

Member
Jul 12, 2011
604
77
Gold Coast
Wow - such a great idea. I look forward to eventually making an attempt at breeding fish. I think it would make such a fun class project! Just need to learn a lot mroe before i attempt it:(
 

marineclass

Member
Jul 12, 2011
604
77
Gold Coast
haha - thanks man, i appriciate it.

Do these cardinals breed easily? I have seen a few people have bred them. Once the lay eggs, how do you move them into the container? I imagine you cant just pick them up and put them in?

Once the eggs have hatched, i see you moved them inot a bigger container - do they stay in here long before they can venture out into the tank?

I accidently bred freshwater angel fish once - they layed the eggs and i thought the were eating them so i removed the eggs from the tank and put them into a bucket - big mistake apparently - I would like to think i should have known however i was only 10 years old at the time. I wasnt expecting them to lay eggs so i didn't know anything about the process and that the fish turns the eggs -haha - next time hopefully they will have more success.
 

Dr. Schell

The Fuckin' Doc
Jul 12, 2011
1,972
1,228
Brisbane
Very easy to breed, the trick is to obtain a compatable pair. The cardinals are mouth brooders. My male tends to eat his eggs after the 3rd week (they brood them in their mouths). To harvest them, I net the male and he quickly spits out the eggs. I am sure that he knows the process. Yes, I move the fry once they hatch, into a larger contained which sits in my display. Takes the fry a few months to get large enough to be released. The container also helps to keep the food density high, so the largae don't have to go far for food.
 

S1L3NT

Member
Jul 17, 2011
18
5
Have managed to get my hands on a mated pair of bangai cardinals, so going to ask a few questions also :D Hopefully I can be successful with it too :)

How do you go about doing the water changes without loosing the fry into the tank? Or have you made small enough holes to allow water circulation to run through and thus remove the problem...

At what day do you usually get the male out of the display?And do you do anything to trigger spawning or just leave them to it.

Thanks mate.
 

Dr. Schell

The Fuckin' Doc
Jul 12, 2011
1,972
1,228
Brisbane
once the pair mature/compatable, it is pretty much impossible to keep them from spawning. I remove the eggs from my male as he has a bad track record. I net him within the tank (I don't remove him from the water) and he spits out the eggs. If kept with the male, the eggs hatch around 3.5 weeks from spawning, and the male will release the fre-swimming fry at 4 weeks. If you removed the male at 3.5 weeks, you would be sure to get all the young. I have large holes in the rearing enclosure, but they are covered with stocking. As my tank has waves, water surves into the container, and then surves out, so it is constantly being renewed wit tank water so no need for cleaning. Cardinals love prawn meat. I but up green prawns and feed this to them to condition the male between broods.
 

S1L3NT

Member
Jul 17, 2011
18
5
Fantastic. Got my mated pair today, have them in the tank never leaving eachother sides so a good sign already. Hopefully they settle in and get to breeding while i have some time still haha. Uni has just started.

Do you strip your male at a certain point of holding? The same way cichlid mouth brooders are stripped I assume?

Appreciate your help. Very helpful for me :)