[Zbrafish] multi-tank system - problems with fish survival

[Sillitti, Joseph (NIH/NICHD) [C]]

How long has the system been set up?  How many fish did you put on the
system when you first added them and how long was the system running
before you put the fish in?  What kind of water are you using to put
into the system?  How much and how often are you feeding?  What type of
water are you setting up the crosses in? 

It seems that you are going through the natural nitrogen cycle of the
system start up.  It is very natural to see ammonia and nitrites in the
system when you first set it up and put fish in.  It takes time for your
bio-media to start growing bacteria to break the ammonia down.

Higher levels of ammonia will bring your pH down so you need to correct
that before trying to adjust for the pH.  To adjust for the pH adding
sodium bicarbonate is probably the easiest thing.  

With the pH at 5 and the ammonia elevated it is not surprising that your
embryo survival is low.

I would not use those fish and just let them sit for a while without
stressing them.  After a few weeks of stable water quality and good
feedings then you should be able to use them again.

Joseph Sillitti, LATG
Aquatic Project Manager
Charles River Laboratories/NIH-Contractor
14G/104A 14 Service Rd. South MSC 5590
Bethesda, MD 20892-5590
Phone: 301-451-1398
Pager: 800-429-1610
Fax: 301-480-1317
Email: sillittj from mail.nih.gov
-----Original Message-----
From: cosgood from odu.edu [mailto:cosgood from odu.edu] 
Sent: Monday, October 23, 2006 2:33 PM
To: bionet-organisms-zebrafish from moderators.isc.org
Subject: [Zbrafish] multi-tank system - problems with fish survival

Hello! I know many labs using multi-tanks systems - we recently
purchased ours from Aquatic Ecosystems. Unfortunately, our problems
began almost as soon as we transfered our first, originally kept in
stand alone glass aquaria, into their new homes. What we see is loss of
embryo viability - the vast majority die within 12-24h after collection
from a separate breeding tank.We think the problem is with the
multi-tank unit - the water pH runs low (@5), we have have levels of
ammonia and nitrates - and we see none of this problem with our
individual tanks. So something to do with the multi tank unit, whether
it's the pump system, the plastic used in the tanks or the reservior,
no clue. Has anyone out there had similar problems? More importantly,
how did you resolve your water quality issues? We've not had much luck
in getting useful advice from Aquatic Ecosystems. I'm hoping the zfish
community will be able to suggest some approaches we could try out.
Resolving the pH problem is probably the simplest issue, but it is a
puzzle that we don't see the problem in stand alone tanks!
Thx for your time - Chris

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