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Help I've just lost 7 zebs don't know why !!
I had a group of 9 .2 separate batches a 5 and a 4 all F1 about 1.1/2 to 2 inch TL
Group 5 I had for 3 months fed on new era pellets all well blue tinges fat bellies
Group 4 bought 4 weeks ago they were fed on tetra prima granular
Tank params temp 84'f ph 6.4 amm 0 nitrite 0 nitrate 0
Water changes 10% x 3 times a week ro water + Marin pro discus ( remineralise )
Sand and slate for decor species tank only
All were well until Wednesday just checked and 7 found dead with fat bellies
There was a couple of them that had ragged dorsal and tail fins just thought that was fighting as they all sat together in the same area
Other 2 are fine did have fat bellies but stopped feeding them instantly seem to be normal pooping everywhere
One of the remaining as ragged fins but he/she could be an original as above
All I can think of is the ph was 7.6 when original 5 were in tank but dropped to 6.4 when there was 9 could it be this or the tetra prima swelling in their bellies that killed them.
Would it be wise to stop using the RO combo and just use treated tap water ph of 7.6?
Please help any advise would be great

I think this topic got lost in the spam, sorry..
How long has the tank been running?
I know a breeder who lost a whole batch of juvenile zebs by dropping his ph to fast, why did you drop the ph like that?
How much do you feed them, and do you feed them anything else then the tetra prima pellets?

Hi thanks for the reply the tanks been running about 8 months I waited a white for it to cycle
The ph was at 7.6 when I had the first 5 in then it crashed to 6.4 when the next 4 were added(possibly due to the extra waste acidic)
I fed them a crushed thumb nail size of tetra prima 6 nights a week (since stopped that and feed new era pellets)
Was Alternating between tetra prima and new era while they were small
Since the deaths have reverted to treated tap water not ro and slowly got the ph back to 7.6
Survivors are looking good
So I'm looking more at PH crashing than the food it's an expensive crash
Any more advice would be good
Thanks

Bakerlad wrote:Would it be wise to stop using the RO combo and just use treated tap water ph of 7.6?

Yes, don't mess with your water just to get PH down, my zebs breeded at PH 7.8 so 7.6 is no prob.

Thanks John
I didn't intentionally lower it , it dropped that low overnight can't understand why as the group were together for 4 weeks
Also the night before the deaths I didn't feed the group as I was working late and lights were out when I got home So it wasn't over feeding

Zebras, and many other seasonal breeders respond to change more than absolute numbers. I have seen numbers from the Xingu near Altamira for dry and rainy seasons- but taken a number of years apart. For TDS I believe it was something like 14 ppm and 83 ppm and pH from about 6.5 to 6.9 or so. However zebras in tanks are pretty resilient and they work fine at higher pHs but not so well at lower ones. As for hardness/TDS- it a change that is important. I have tried it two ways. Raise the numbers for dry season, with additives and water change regimen and then use tap to drop them, or else start with tap and then use ro/di to drop it. One method was roughly 150 and 75 ppm and the other about 85 and 40 ppm. I didn't not pay attention to pH at all and I assume it didn't change much.

The other thing to remember is that the dry season takes months to build to its highest level and then the onset of the rainy season is fairly rapid in terms of how much change and how quickly it happens. But the babies are born with the best water for them arriving for their first few months.

The upshot is a pH of 6.5 is the low end and close to as high as 8 or so seems to have been the workable range across the world of folks who spawn them in tanks. However changes are relative not from one end to the other. The amount of change should be relative to where you start in that range. And too much can be a problem. TDS/hardness has much more latitude than pH, imo.