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alright guys,

iv recently got a group of 5 corydoras weitzmani's to try and breed. iv had them for about a month now and iv noticed there black patches are not as dark as when i first got them, most of them seems to be going duller brown but 1 or 2 are still normal. there was a little amonia/nitrite spike in the tank when i added 10 little shaoling fish into the mix but this was brought under control very quickly and everything seems fine now. should i be worried?

Water parameters:

PH - 6.8
Nitrite - 0
Ammonia - 0
Temp - 75 degrees.

anyone...?

Hi Andrew

One possible reason for your Weitzmani to loss their colour could be substrate, if it's pale then this could be why. They do seem to develop a better colour over darker sand. Also add some leaf litter (oak or beech and catappa almond work well), this will help put them at ease and again promote better colours. You might also look at your lighting, it may be too bright, they do prefer subdued lighting.
Stuart

thanks alot, the sand is quite pale.... iv got some indian almond leaves in the tank with them and they love to hide under them. ok thank you, as long as they are not ill then im happy! i was just worried about them.

all the best,

andrew

Andrew,
My group did pretty much the same thing. Out of the 5, two (an active pair) retained their colour. The remaining three (I assumed all female) went a duller colour with none of the pink or bold markings.

However, after live food feeding (daphnia for me) and lights out, all fish tend to get active and the duller ones resume the typical markings. I have recently split the group (in an attempt to improve fertility from the one male)leaving the 2 bold colouration adults in 1 tank and the remaining 3 in another. The 3 duller ones have since coloured up nicely and have spawned (which was a surprise, I thought they were 3 females). The two remaining fish have spawned a few times since. I've also added some juvenile males to the pair, to try to improve fertility and stimulate the female.

I don't know if its a dominance thing, although I suspect it is considering my experience. After 9 months with these fish I am pretty sure they are one of the more nocturnal cories - very secretive during the day. Spawnings have usually taken place early morning or late evening. And, yes they are avid egg-eaters as others have testified.

Good luck,
Mark.

I have two peppered cories that is dulling now
The one that isn't dulling is the least active... my substrate is brown, so I don't thing background color has anything to do with it, although the LFS had them in black graveled tank and the color was the brightest then.

Should turning one side of the tank darker help? like adding darker substrate to one side and not mixing them all together?

thanks!

While your Cory, weitzmanni have spawned which is a fair indication that you are on the right track, I would consider reviewing their water chemistry parameters. C. weitzmanni are not yet domesticated and a close match to their native waters maybe indicated.
I would add liberal feedings of enriched bbs and add supplementary vitamins to their foods. Tetra Color Bits are a useful delivery vehicle for adding VitaChem to their diet. Lots of live worms and soft acid water darkened with a blackwater additive may help bring out their colors again. I am trying to get some of these Corydoras myself but the prices are very high and I want to have at least 6 but preferably 12. $$$$$$

i got 6 these cories, and the only ones in my country.
They have also gone pale. After i added some cover (eg plants and clay flower pots) for them and also some driftwood the colour has come back. The colours are not really orange yet tho but it is improving.
I need to change the substrate to sand aswell, because when i feed them worms they go missing under the gravel!!

What I have done with all my Corydoras breeders and fry tanks is add about 1/8 inch of very fine sand. This is just enough to give them something to do. I believe they are more at ease with some sand than they are without. I feed mine California blackworms or Tubifex in the past and the worms eventually settle into the sand but their tails are always waving in the currents. The sand is so thin that the Corys easily find and eat them all. The other nice feature of this method is that the sand is too thin to go anaerobic.
I just add a couple of pieces of driftwood and potted plants to complete the aquascape.

I've noticed the same thing with my group of 5 adult C. weitzmani. I've removed the oak leaves in the tank in preparation to welcome 10 new ones, juveniles. I wanted a clean tank and a clear view with the new ones, to be able to see everyone and check on them. But the adults didn't seem to enjoy the fact that the leaves disappeared, they went pale and their normal black patterns went dull grey. This has been the case for a few weeks now, and at first I didn't connect the pale colour to the removal and disappearence of the leaves.

20 minutes ago I read the tip about adding black water extract to the tank, so I went straight in to my fishroom and did so. While sitting there and watch the reaction, it was like someone turned on a switch! The colour came back! Just a few minutes later they were jet black again! They started a restless swimming about the tank and my face had a big smile on it:-)

It works!
PS!
I use AquaMedic "Amazon" black water extract.

The new addition to the tank, 10 lovely juveniles I bought yesterday from Ian Fuller, is also happily swimming around and eating like there's no tomorrow.
This photo was taken yesterday, just a couple of hours after releasing them in to the tank.

<img src="http://nettakvariet.no/forum/attachment ... 1164549119">

I was told on Corydorasworld that it could be a dominance thing the 'sub' fish tend to lose their colour.

might make my own blackwater addirives, I found this on another forum, what do you think guys?

2L of DI or RO water
20-25 Oak or maple leaves from backyard
2 oz peat

1. Collect clean, moldless leaves in bucket
2. Pour in RO or DI water
3. Drop in peat
4. Smash leaves and peat with fingers
5. Let sit for 48 hrs
6. Pour through coffee filter
7. Store in air-tight bottle