Breeding Parameters.

[Hf21]

Hi all,
I absolutely love Cory's and want to start doing more breeding this year however I was just wondering roughly what kind of water parameters people have got their Cory's to breed in. I have gold lazer cw10, duplicareus, sterbai and venezualean orange (I'm not sure on the correct name for this breed if I'm honest). They are all happy however my water is on the harder side ph 7.6, kh 4 gh 12. I realise they are a softer water species but have people managed to get them to breed in harder water? I would be interested in what success people have had in different water values. I have tried to soften my water using 50/50 ro to tap water but as the kh is so low I have to buffer it which by the time its buffered brings the other values back up.

 

[seangee]

As long as you have no hard water species there is no need to buffer. As mentioned elsewhere I found cory fry in my community tank the week. That has 100% RO water and nothing else. GH 0, KH 0 and pH around 5.6 using a digital meter.

 

[Hf21]

As long as you have no hard water species there is no need to buffer. As mentioned elsewhere I found cory fry in my community tank the week. That has 100% RO water and nothing else. GH 0, KH 0 and pH around 5.6 using a digital meter.

I thought all fish needed some minerals? Would zero kh not cause ph swings?

 

[seangee]

I thought all fish needed some minerals? Would zero kh not cause ph swings?

Answered in your other thread. Most South American water courses have very soft water and almost no minerals. The fish have adapted to this (over thousands of years). Your fish will be noticeably brighter and live longer if they have the same. If you have shrimp or snails these do require minerals (in the form of GH) but your 50/50 mix will be fine without buffering.

FWIW MTS are fine with 0GH and KH.

 

[Byron]

I also responded on buffering in the other thread. As you ask about cories here, I will just say that I have 40 wild-caught cories representing about a dozen species, and I have seen all of them spawning, and while I just let nature take its course I do see fry now and then. When I had my 115g and then 70g tanks with 50-60 cories, every time I cleaned the canister filters I found one, two, three, and once five cory fry in the bottom; these I raised in the 10g with the group of spawning pygmy cories until they were large enough to put back in the main tank. With zero GH and KH, and a pH that is around 5 (maybe lower, I have no test below 5) they are quite prolific.

I am not sayinng you must have this chemistry, just point ing out that "buffering" is not at all needed and only complicates the water chemistry for no benefit. With soft water species that is. In harder water some species might be more difficult, but I know other members have had spawning in moderate hardness.

In a discussion opn his site CorydorasWorld last week, Ian Fuller mentioned that he uses RO water with no buffers for his cories, and the pH is somewhere around 5 and he has tanks of wild caught cories spawning. He noteed that these parameters prevent bacterial infections in the fish, so another benefit.