My fish are slow growers...

[Capo]

Hello,
OK, well as the titile says, my fish are slow growers.
Well i think they are, (i have a few fish ill tell you about)
1st= Murray cod - had him since he was about 5cm, grew to about 10cm total length.....it took around 3 months, something wrong with that?
2nd= Archer Fish - got him about 5cm hes about 7-8cm now, that ook about 4 months...
3rd= I have some Golden Perch, started off about 5cm, and 2 months later.....dont think i have noticed any growth..... maybe hardly 1cm if your lucky.
4th= well, this is the only fish i have noticed considerable growth, my little Jardini. I got him only 1 month ago, and he has grown more than 1" so far, im impressed!
5th= not a fish though, but i have a Gippsland Water Dragon....i havent noticed any growth at all, he is about 20cm long now head to tail, and about 6cm SVL. Ive had him for 1 1/2 months.

All of these animals i feed every day. Except the murray cod, i had to give him away. But yeah, I only feed once a day (is that why? ) and im sure i feed them enough (i feed 'till i think is enough, usually when i see their stomachs bulging) The fish eat varying foods, alternating days from,
-pellets(hikari gold)
-frozen plankton
-frozen blood worms
-crickets
-occasionally live black worms and sometimes i find earwigs from the backyard.

I dont see whats going on! I saw Hardboiled's Murray cod and it has (look slike it has) grown at least 20cm in 4-5 months!
It is really depressing!

 

[PhullTank57]

Hmm??... okay, a couple questions first.

- Are all these fish Housed in a single tank??... or in seperate numerous tanks?
- Size of Tank(s)?... gallons?
- Water changes?... how much and how often?
- Possible Parasites?... internal?

 

[hardb0iled]

There are few things which effect the growth rate of fish, the main reason my cod has grown so quickly I think was,

1 - (this is just a theory) I'm pretty sure he was underdeveloped when I got him, according to the breeding season for MC, a fish my size should not have been available at the time of year I found him, so I'm thinking he was left over from the previous breeding season and has been underfed and kept in crowded fish store tank for a long time. When I got him and started doing right by him(good water, lots of food, bigger tank) his growth rate took off and he started catching up to the size he probably should have been according to his age?

2 - I kept him in a tank with a temp of about 24celsius, this is apparently the optimal temp for growth and actvity in MC's(remember they are a temperate water species so generally live in colder waters for most of the year). I have spoken to other MC owners and they have actually reduced the tank temps after their fish has reached a certain size otherwise they outgrow the tank too quickly!

Also I was powerfeeding mine for a while as he was sharing a tank with my Bala Shark, the only way I could get him to stop harassing the Bala Shark was to make sure his belly was always full! When he's full he's happy to go nap under a log, but as soon as his belly shrank again(usually in about 6-12 hrs!) He was full beans and back enforcing his position as owner of the tank!

Sorry to hear you had to give yours away, they do take some determination to grow out though, seeing that they need such a large tank and you cant keep anything with them!

 

[Capo]

to Phull tank57,

-I have Numerous tanks. Right now the Archer, Golden Perch and Saratoga are housed together in a 75Gal (48x20x18). The murray cod does not live at my house anymore. The tank they are in is at 29C, im thinking i should remove the Golden Perch, but hes doing fine ATM.

-Water Changes, I used to rarely do water changes, and they would be large amounts like over 1/2 the tank every month. But now they are more frequent say 25% every 2 weeks. I didnt tink every week would be necessary as i dont have a very large bio load since there are only 4 fish in the tank.

that help???
Actually i like the idea of that powerfeeding. Did you just use pellets?
Because my Archer and Saratoga are always bullying eachother.
Cheers, oh and my MC was at 24 degrees too.... I had him with some tropicals when i had him.

 

[hardb0iled]

Actually i like the idea of that powerfeeding. Did you just use pellets?
Because my Archer and Saratoga are always bullying eachother.
Cheers, oh and my MC was at 24 degrees too.... I had him with some tropicals when i had him.

hmmm dunno, sounds like you were doing everything right? Could just be genetics too? I read an article about a Murray Cod aquaculture project, they purchase their fry from specialist breeders, then grow them out to a size suitable for table fish and sell them to the resturaunts etc. Anyhow they said that they purchase their fingerlings from one source as they have found the genetics at that source to be superior, as they grow quicker and at a more even rate than fingerlings purchased from another breeder?

As for water changes, I'd at least aim for 30% water change weekly. No biggy if you miss a week but more often than not try and change some water weekly. The best thing you can do is buy a Nitrate test kit. This will easily tell you if your water changes are being done often enough. I have a 450l tank which I try to do 20-30% water changes weekly. I just recently tested it for nitrates and they were very high! The fish havent been bothered by it, but better to fix it before they are.

As for power feeding - well MC was easy to power feed because he's a pig! I mostly fed him on white bait(silversides). At his current size I'd feed him probably abour 6-8 of them at each feeding, I can usually tell when his belly is swollen enough! I then leave him and as soon as he is hungry again he comes to the glass. I fed him whenever he came to the glass - up to 4 times day! Usually 2 or 3 times a day

 

[hardb0iled]

oh yeah, I would probably try and reduce the temp of his curent tank a little if its always set at that temp, 29 is a little high to keep him at indefinitely. I know my MC didnt like it when the tank temps got up towards 30. I now try and keep him at 22(which is about room temp as I dont use heaters at the moment), but his tank is getting up to about 26-27 on the hotter days.

PS. heres some pics of an MC I visited on the weekend, this guy must be around 60-70cm and is housed at Boronia Aquarium in Melbourne





The tank he is in at the moment is way too small, but apparently they have a 6'x3'x2' coming down from Sydney in the next few weeks to house him in