Wrigglers won't go free swimming?

Hi everybody,

My angels breed every 3 weeks or so but I can't seem to keep the fry alive. I remove the father shortly after the eggs are laid because he eats the eggs. The mother seems to to her job reasonably well, she relocates the fry to different parts of the tank but my problem is the babies don't seem to get past the wriggler stage cause they either end up on the bottom where they are stuck by the little sticky thing on their head or they get stuck together in longs strings or balls of babies, all stuck together by the little sticky thing on their head. They get to about 6 days old from when the eggs are laid and are still either stuck on the bottom or stuck together. Please help.

Cheers Ryan

What variety(s) are the parents?
What temperature is the tank?
What are your other water parameters?
Do you have a light on the tank?

I run my tanks at about 80f (27/28c) and have known some batches to take as little as six days from being laid, up to as long as, on one occasion, 9 days before they went free swimming.
Before free swimming it's quite normal for the fry to remain stuck together, and once they go free swimming, it's quite normal for parents to gather the youngsters up as soon as they "take off" and spit them back on to the leaf or wherever else they're keeping them. eventually the youngsters overwhelm their parent's abilities to keep them hunkered down, but when the batch is fairly small, I've known the parents to keep the young pinned down for too long. for the first few days of free swimming, the parents will also gather the shoal together and back onto a leaf or slate before light's off.

Some varieties seem more problematical and sensitive at this early stage, and poor water quality, or the diet of the parents may also be an issue. Finally I've found on occasions that stripping and cleaning the breeding tank (I usually bleach it with miltons - the baby bottle bleach) before draining and refilling can help to improve hatch/success rates, I suspect that some bacteria or other pathogen to which the parents are immune, my affect the youngsters.

Thanks for the reply Pteropyllum,
My water parameters for the last batch of fry were as follows.
Temp, 29c
Ammonia, 0ppm
Nitrite, 0ppm
Nitrate, 20-30 ppm.
Tds, 130
Ph, 7.2
The parents are female black and white striped one (not an altum) and male is a black lace, they are both quite large and normally have about 300-400 eggs with most hatching to wrigglers. The eggs do get abit of fungus on them but the mother moves them away when they turn into wrigglers.
I had been doing about 25-50% water change daily to suck the waste from the mother away replacing with water with the same tds, ph and temp as the tank.
Thankyou for taking the time to respond.

Cheers Ryan.

I forgot to mention I have them in a 20 gallon breeder bare bottom with a sponge filter. The tank has been established for about a year.

Water quality sounds good. I have noticed that blacks can be slightly slower to go free swimming, but they shouldn't be too hard to raise.
If you've had several previous batches in that tank, I might be inclined to bleach and reset it, but make sure you use a mature filter.
Personally I don't do water changes when the parents are tending eggs, wrigglers or free swimmers, but I know many that do. If you want to keep doing water changes, you could try doing smaller ones, the fry are much more sensitive to fluctuations in water temperature or chemistry than are the parents.

I got some methylene blue and added it to the tank on the last spawn and they're 9 days old now and there are about 200 free swimmers. Fingers crossed they survive.

Very good - without MB things can go downhill quite quickly, one bad egg affects the 6 next to it, then those six affect another 6 each and it's woolly eggs for breakfast!