Calvus Fry - keep dying on me!!

I keep losing brood after brood of black zambian calvus fry. I've tried the following:

1. Keeping them in a breeder net in the main tank (bottom blocked from adults) = they lasted about 6 weeks

2. Keeping them in the parent tank (one has lived for about 4 months!- but thats it) they last about 3-4 days then disappear

3. Moving them immediately to a 10gal tank at first signs of free-swimming. They lived for 8-10 weeks.

Water parameters are good (frequent small water changes) - they eat well (microworms) water about 78 degrees, sponge filter and airstone. Is there anything you know of I could try?

Hi and Welcome to the forum!!! Sorry to hear about the problems with the calvus fry, they are touchy lil fella's. My calvus have yet to spawn, but my comp's spawn regularly. I have a fry chamber built into my tanks, the idea was to keep them in the same water they were spawned in for a while. This would be similiar to you keeping them in a breeding box. I think another plus to going this route is that because they are in a smaller area it's easier to get the food to them. As you well know, the fry like to sit on the bottom and at first they're not "looking" for food, it basically has to come to them. In a ten gallon tank you would have to put a lot of food in there to keep a good bit of it right in front of them. My suggestion would be to keep them in a breeder box at first, until you see that when they notice food they start moving around looking for more which won't take long, then move them to the ten gallon. I also feed microworms along with NLS Growth Formula crushed into powder. I was starting them out with microworms but it took a while for them to start eating the nls, they preferred the microworms (so it seemed). The latest batch I started feeding the nls powder first which they took to right away, then I started feeding microworms every couple days with daily nls feedings. This batch is eating more aggressively than any of the previous batches, hopefully they'll grow faster because of this. Another key is keeping the bottom clean since they spend all thier time sitting on the bottom, the more you can vacuum the bottom, the better your luck will be with these guys. That will also provide a lot of small water changes which they will appreciate. So in summary,

1) Keep them in the breeding box until they are eating aggressively, then move to the ten gallon.

2) Add NLS Growth Formula to thier diet (crushed into powder)

3) Vacuum the bottom as often as you can making sure not to change too much water at a time.

Hope this helps, please keep us posted and feel free to post up some pic's, we'd love to see and hear about all of your tanks

Thanks for the help!! I did already move them to the 10gal. earlier today. should I set up a breeder net in the 10gal and put them in there so I can get the food to them easier? or do you think trying to catch them etc will stress them out more than its worth...

I'd see how it goes, give em a couple days and see if they seem to be eating when you feed them. I would be sure to put plenty of microworms in there and vacuum the bottom every other day. If it seems they're not doing much eating after a couple days then go for the breeder box in the ten gallon for a while. Another thing to consider would be dividing the ten gallon for a while, until they start moving around more.

I've never raised any Tang fry, but I'll add a couple of tips that I've found helpful with my mbuna. When keeping them in a breeder box or net, I add an airstone set to a gentle flow to create some circulation and exchange of water with the tank. I know this works because I can see the powdered food moving out through the slots. It also stops the formation of the surface "scum" that sometimes accumulates on top of water that doesn't have any movement. I haven't done any experiments to compare, but it sure seems like the fry in boxes with the airstones grow faster.

Another thing that I've found helpful is a turkey baster. I use it to squirt powdered food or frozen baby brine shrimp into the tank, to get it closer to the bottom where the fry are. It also comes in handy to suck up poop in the breeder boxes if the circulation isn't strong enough to remove it.

Good luck with these fry. It must be very frustrating to have them live for a few weeks and then die.

Excellent tips Betty!!!

see quick response way to go guys

I agree with Mike maybe try to vary the food to get them eating more than microworms. Growing out baby brine shrimp is very easy and all of my fish readily eat it. Aura's idea of using the turkey baster is also how I feed my fry.