PDA

View Full Version : Murray Cod not well - any ideas?



Yabbies4me
21st September 2010, 16:49
Here I was a few weeks back bragging that my 5yo Murray cod was a picture of health and I very rarely check the water, only pH every few weeks. I'd figured out years ago that the less I tinkered, the better she was.

Well about 4 weeks ago I was adding a few lumps of limestone to the tank, I add two or three fist sized lumps to the 600Ltr tank when the previous lumps have just about eroded away, normally about every twelve months.

This time one of the lumps was a fair bit smaller than a fist, probably a little larger than a golf ball, but with irregular, jagged edges. As I put them in the tank the cod came darting over and swallowed the smaller lump, it then preceded to try and regurgitate it, it took about a minute for her to dislodge it, but she finally managed to spit it out.

The following day she wasn't eating, but I'd completely put the limestone thing out of my mind. I left it for a few days and she still wasn't eating, so I decided I'd better do a water check. The pH had dipped to low 5's and the Amm had spiked to 4.0, Nitrite was 0.0 and Nitrate was 10. This told me the filter pads needed cleaning, I looked, they did, so I cleaned them and did about a 20% water change, then I slowly increased the pH to 6.5 over a couple of days.

I thought about putting some Amm-Lock in to tie up all that Amm, but was talked out of it by a fish bloke. Well, the filter and bacteria started working again with a vengence and converted all that Amm to Nitrates which spiked to 80 within a few days! :eek:

Amm dropped to 0.25, Nitrite still 0.0, so I've been doing 20% water changes every third day for last 3 weeks, nitrates dropped to 40, but today have spiked back up to 80 again. :eek:

I don't know why Nitrates have spiked, she has hardly eaten anything for 4 weeks. A week after this all started she ate for two days then stopped eating again. She hasn't eaten for three weeks now.


Q: Why have the Nitrates re-spiked now when they were coming down with the water changes and she hasn't eaten for 3 weeks?

Q: Do you think she may have damaged her throat sphincter thingy with the limestone and that's why she's not eating?

Q: Or, do you think the pH and Nitrates issue may be the problem?

Any opinions or advice would be greatly appreciated!... :p

Castaway
21st September 2010, 18:24
As I understand it, fish give off ammonia through their gills as well so it matters not if they don't eat anything, as long as they are alive they will continue to exude some amount of ammonia. With a 5 year old Murray Cod I take it that its a pet now and not something you intend to eat?

Yabbies4me
21st September 2010, 18:31
That's correct Castaway... she and her siblings started out as future fish 'n' chips... she took care of her siblings one by one, and then developed some character, so now I couldn't possibly eat her. Friends have suggested it... but it just wouldn't feel right!

Castaway
21st September 2010, 18:41
Well I think you've done very well to keep her so long in captivity as people do say that Murray Cod can just suddenly die - so lets hope yours is okay.

RupertofOZ
21st September 2010, 19:30
Nitrates will not affect your fish... unless at a level of 400+ppm...

As your pH is now around 6.5.... there's absolutely no need to do any further water changes, indeed there probably wasn't in the first place...

As much as you think your bacteria colony is back to health... the nitrate spike, and trace ammonia readings suggest that, as yet, your system hasn't fully recovered to balance after (no doubt) a complete crash with pH below 6.0...

As to your cod not eating... It's quite possible that it has suffered damage... possibly "unhinging"/dislocating the bottom jaw....

Yabbies4me
21st September 2010, 19:42
Cheers guys!...

That's not a good diagnosis Dr Rupe... No disrespect, but geez I hope your wrong, coz I'm guessing there's no recovering from that?

RupertofOZ
21st September 2010, 21:13
It might, but slowly....

Barramundi suffer from jaw dislocation quite commonly....

Yabbies4me
23rd September 2010, 19:56
I think she may have damaged her throat sphincter thingy!

She started to show interest in feeding today, coming up the end of the tank where I normally feed her. I defrosted a regular sized river prawn, about 8cm, and dropped it in. She went to pounce on it then changed her mind.

Bearing in mind the dislocated jaw idea I then tried a small river prawn. She pounced on that and opened her mouth fully. It appeared as though she had swallowed it, but she then regurgitated it. she repeated this procedure another couple of times then gave up.

APDude
24th September 2010, 11:45
Now, I'm no expert, but that sounds like a "Throat Sphincter Thingy" problem to me :frown:

Yabbies4me
24th September 2010, 14:21
My thoughts exactly!...

I think she's gonna be alright, I peeled a prawn and cut in three and dropped it in the tank. she didn't eat it at first, but when I came back a few minutes later she'd eaten them.

:p

dufflight
24th September 2010, 17:32
A few small yabbies to move around and get her back in the mood. I dropped a yabbie into the glassed in overflow and now the Cod spends all its time watching yabbie TV. Just can't work out why it can't eat it.

Yabbies4me
24th September 2010, 19:10
:(
Yabbie TV... Piss funny... Cruel, but piss funny!