C121 spawning

mummymonkey · Post by **mummymonkey** » 23 Mar 2005, 19:29

Searching the records I see there are a few records of this species breeding. Just thought I'd add a picture of mine:

SanDiegoFishes · Post by **SanDiegoFishes** » 25 Mar 2005, 01:21

Awesome! Great pic too

How many eggs did they lay? Did they have a preference of where they placed their eggs?
Barb

mummymonkey · Post by **mummymonkey** » 27 Mar 2005, 22:30

SanDiegoFishes wrote:Awesome! Great pic too How many eggs did they lay? Did they have a preference of where they placed their eggs?
Barb

So far I've had two spawnings 4 days apart; a smaller (26 eggs) spawn to start with then a larger (54 eggs) today (Sunday 27th). The female spawning today was the largest specimen I have.

pH 7.0
KH 1
Gh 2
Temp - 75C
Water changes (same temp) of 25% twice a week for last 2 weeks
Filtration - box filter and small power filter
Tank - 18x12x12 no substrate (Moved from similar 36x12x12 when spawning started)
Spawning media - sunken & floating wool mops and Java fern on bogwood
Fish 7 specimens, I think 3 females and 4 males
Floating plants covering half surface (Indian fern)
Food - frozen bloodworm, grindal & white worm, mixed flake

These fish have been in a grow out tank with a brood of Mikrogeophagus altispinosus for the last couple of weeks. I've been doing frequent water changes and feeding heavily as above. As soon as they started to spawn I moved then into their own 18 inch tank.

The eggs were deposited on the tank bottom, tank walls, under the heater, on the power filter, on the Java fern and even on the bogwood. About half were stuck in the sunken wool mops. The floating wool mops were not popular with only a couple being found there. The first (smaller) female prefered the tank bottom and sides, whilst the larger female used the sunken mops most.

Of the original 26 eggs, 11 were infertile and 15 still remain and are quite dark but have not yet hatched.

All the second lot seem to be fertile.

The eggs are large, knocking on for 2mm.

JoL · Post by **JoL** » 29 Mar 2005, 13:13

Hello!

Congratulations!
The time in year they are spawning is very interesting, in my tank they started november last year an finished in march.
I've made the same experience with the water chemistry. It seems that they need soft water for spawning.

Greets,
Joachim

Post by **corybreed** » 29 Mar 2005, 23:40

Good job! I have 5 c-121 and will soften the water this weekend. Keep us updated on your progress with the eggs.

Mark

JoL · Post by **JoL** » 30 Mar 2005, 08:39

I've got every time about 90% fertile eggs (except one time, where every egg was infertile). In the first 3 weeks i've lost every time about 25% of the young c121. But it was enough to get up now about 100 young C121

Joachim

mummymonkey · Post by **mummymonkey** » 30 Mar 2005, 10:36

Another 20+ eggs yesterday. It seems they like to spawn in the afternoon and evening.
The first batch are only now, after 7 days, hatching out. I checked with another thermometer and the temp is actually 72F, which explains the long hatching time I guess.
Very large yolk sacs.

mummymonkey · Post by **mummymonkey** » 11 Apr 2005, 09:11

Well the adult fish continue to spawn every 2 or 3 days. Always in the afternoon/evening. I've collected over 200 eggs up till now.

Hatch rate is reasonable, around 80%. Most of the unhatched aggs are infertile and can be spotted soon after laying.

The problem I have now is dead fry. They seem to hatch and absorb their yolk sac no problem; then snuff it. I'm picking out several dead fry of the same size (8-10mm) each day.

Also starting to see 1 or 2 little fry in the parents tank.

Any ideas on how I can improve the fry survival? I'm feeding microworm, ZM fry food and also have bbs available (though not fed any yet).

JoL · Post by **JoL** » 11 Apr 2005, 10:57

Hello Mummymonkey!

I have the same problem with dead fry. Here it's about 25%. I'm feeding fresh breed artemia. I don't know the reason, but normally it stops one day and the rest than is not a problem. I've tried with sand, without sand, different tanks and so on and so on. I've found no reason. I'm now accepting the 25% dead fry.
Good luck with your fry!

Joachim

corydorus · Post by **corydorus** » 21 Apr 2005, 06:28

I have similar amount of dead fry for duplicareus as well.

Probably i will try more water change with main tank water daily to see the results.

mummymonkey · Post by **mummymonkey** » 26 Apr 2005, 00:08

I have continued to suffer fry losses though not as bad as during the first week. I noticed some of the fry had missing or abraded pectoral fins so I suspected a bacterial infection. I've therefore added a thin layer of sand to the tanks with fry to see if things improve.
Luckily the adults continue to spawn and I still have over 100 fry in various stages of development. (Now in 3 x 10 gallon tanks)

: c121_fry_26days.jpg (14.81 KiB) Viewed 1507 times

corydorus · Post by **corydorus** » 26 Apr 2005, 07:42

I am learning as well.

Your frys look the same as my C. duplicareus. One or two frys still dropping off for me too.

Actually my frys at certain stage of fry developement has
their dorsal fin turns black !

But I have only 20 frys to play with now. Just collected 4 eggs yesterday. Kind of disappointed. Is the least recorded batch i have seen.

Done a major water change on main tank. Hopefully I got a bigger batch today, if any.

mummymonkey · Post by **mummymonkey** » 03 May 2005, 14:30

Well my fry losses have dropped from 5 or 6 each day, to only 3 (very small) fry lost in the 8 days since I added the sand. It seems this was the cure.
I have a neighbour who is a soil scientist (at a nearby agricultural research institute) and he thinks that a thin layer of sand will allow a different species of bacteria to live on the bottom, and probably a greater diversity of bacteria. Having just a glass bottom, especially when sponged daily as I did, will most likley encourage the growth of a single species, the one most adapted to attach to smooth clean surfaces. If this bacteria also happens to be lethal to fry, especially bottom living fry such as corydoras, then the results are predicatable.
Anyway, I now have approx 200 fry of various sizes, another 50ish eggs ready to hatch, and the adults are spawning as I type this post. I have 2 questions for those with experience in raising large numbers of catfish fry.

1. The last couple of spawns have resulted in slightly smaller eggs. Is it now time to seperate the fish and give them a rest?

2. How many fry/gallon when raising fish to sellable size? I have limited space so I could just about stretch to 70 imperial gallons over 4 tanks. (12 x 12 on the sides)

: c121_fry_1month.jpg (23.07 KiB) Viewed 1507 times