I've always thought it would be interesting to have saltwater fish breed in one of my tanks. I've had it happen multiple times with a variety of freshwater fish, but until recently, not with any saltwater fish. I had really hoped our black and white occellaris clowns (which we've had pretty much since the beginning of our saltwater adventure) would mate, then our ORA naked clowns, but the clowns just aren't cooperating for whatever reason. 
Then, I decided to get a pair of Banggai cardinals. They've been in my tank for what seems like no more than 4 or 5 months, and wouldn't you know it, they've mated. Very exciting, as this tank is in my office at work and many of my coworkers (we're all biologists) stop by frequently to see how things are progressing.
While I've not taken the time to read the entire document, this PDF is quite informative about Banggai cardinals, and the parts I've read have been helpful to me.
Thursday, January 28: Observed the smaller cardinal of the pair (now known to be the female of this pair) shaking and twitching about all around the larger cardinal (now known to be the male). Both cardinals ate their normal fill of PE Mysis.
Friday, January 29: The larger Banggai has a noticeably full mouth and flared out opercula. The same fish also has no interest in food at all. While this fish was thought to be a male all along (more square jaw with a noticeable "pouch"), it is now confirmed.
Oh man, so it's pretty clear now that the cardinals have layed eggs, seemingly overnight on January 28. Days go by and the male cardinal continues to ignore food and mostly hover in one spot under an overhanging candy cane coral. Fast forward now...
Wednesday, February 17: Based on the banggai cardinal "manual" linked to above, the eggs should have hatched on this day, give or take a day.
Since a day or two after February 17, we can definitely tell the eggs have hatched. The fry are visible within the male's mouth and have grown increasingly active. They literally are miniature versions of their parents -- stripes and all (well, not the spots yet). The "manual" says we can expect the male to release the fry any day now as of February 23 (most likely to be released at night). As of this moment, the fry remain within the male's mouth, but he is clearly struggling to hold some of them in.
In the wild, Banggai cardinal fry are known to use a long spine urchin as shelter. Even a quick Google search will show pictures of Banggai fry doing this in captivity. The other fish in the tank are my ORA naked clowns, which I just know will enjoy a tasty meal of cardinal fry. What to do, what to do... Well, of course, follow the "manual" and build an artificial urchin! The manual suggests using plastic wire, which I could not find, so I went with 8" black plastic ties.
Step 1: Drill holes in the 2" PVC cap. I started out by making a cross pattern, then made it an asterick, then drilled the areas in between to finish up. I did free hand drill it with a hand held drill, so it's definitely not perfect, but I'm going to bet that it doesn't matter.
Step 2: Begin inserting the plastic ties. Important note... Do not pull the plastic ties all the way through at this point. Because the ends that the ties zip through are bigger than the rest of the tie, they begin to block the holes drilled in the PVC cap. It's much easier to feed the later ties into the holes if the ties inserted early on are only pulled through about 75% of the way.
Step 3: Finish inserting the plastic ties. It doesn't look too bad, if you ask me. Then again, I'm not the one that needs convincing. Oh, btw, in case anyone's wondering, I used exactly 65 plastic ties to make this artificial urchin.
Then, I decided to get a pair of Banggai cardinals. They've been in my tank for what seems like no more than 4 or 5 months, and wouldn't you know it, they've mated. Very exciting, as this tank is in my office at work and many of my coworkers (we're all biologists) stop by frequently to see how things are progressing.
While I've not taken the time to read the entire document, this PDF is quite informative about Banggai cardinals, and the parts I've read have been helpful to me.
Thursday, January 28: Observed the smaller cardinal of the pair (now known to be the female of this pair) shaking and twitching about all around the larger cardinal (now known to be the male). Both cardinals ate their normal fill of PE Mysis.
Friday, January 29: The larger Banggai has a noticeably full mouth and flared out opercula. The same fish also has no interest in food at all. While this fish was thought to be a male all along (more square jaw with a noticeable "pouch"), it is now confirmed.
Oh man, so it's pretty clear now that the cardinals have layed eggs, seemingly overnight on January 28. Days go by and the male cardinal continues to ignore food and mostly hover in one spot under an overhanging candy cane coral. Fast forward now...
Wednesday, February 17: Based on the banggai cardinal "manual" linked to above, the eggs should have hatched on this day, give or take a day.
Since a day or two after February 17, we can definitely tell the eggs have hatched. The fry are visible within the male's mouth and have grown increasingly active. They literally are miniature versions of their parents -- stripes and all (well, not the spots yet). The "manual" says we can expect the male to release the fry any day now as of February 23 (most likely to be released at night). As of this moment, the fry remain within the male's mouth, but he is clearly struggling to hold some of them in.
In the wild, Banggai cardinal fry are known to use a long spine urchin as shelter. Even a quick Google search will show pictures of Banggai fry doing this in captivity. The other fish in the tank are my ORA naked clowns, which I just know will enjoy a tasty meal of cardinal fry. What to do, what to do... Well, of course, follow the "manual" and build an artificial urchin! The manual suggests using plastic wire, which I could not find, so I went with 8" black plastic ties.
Step 1: Drill holes in the 2" PVC cap. I started out by making a cross pattern, then made it an asterick, then drilled the areas in between to finish up. I did free hand drill it with a hand held drill, so it's definitely not perfect, but I'm going to bet that it doesn't matter.
Step 2: Begin inserting the plastic ties. Important note... Do not pull the plastic ties all the way through at this point. Because the ends that the ties zip through are bigger than the rest of the tie, they begin to block the holes drilled in the PVC cap. It's much easier to feed the later ties into the holes if the ties inserted early on are only pulled through about 75% of the way.
Step 3: Finish inserting the plastic ties. It doesn't look too bad, if you ask me. Then again, I'm not the one that needs convincing. Oh, btw, in case anyone's wondering, I used exactly 65 plastic ties to make this artificial urchin.
Another important note... When pulling the plastic ties through the holes that were drilled so they'd intentionally be a little tight and hold the ties securely in place, a fine "thread" of the plastic ties gets shaved off the edges of the plastic ties. Removing those shavings is probably a good idea, however, a rinse under the faucet doesn't really help. I had to shake the urchin dry and remove them all by hand. Ugh...
Step 4: Place the urchin in the tank (after a good rinsing just to be safe). Please ignore the caulerpa that's begun to overrun the tank, and the less than stellar BB pic.
Apparently, I didn't do too bad of a job, as both the male and female cardinals have been moving in and out of the artificial urchin throughout the day today. Now, we just wait for the fry to be released... Everyone's very excited!
The male Banggai in the artificial urchin.
