koura Dead?

[knightmarc]

Went in to work to do a water change and feed my koura in my tank there to find him upside down at the front of the tank, no reponse to picking him up but can see a small twitching of one of his legs when I put him back so wondering if he's starting a shed?

Water should be ok as have a bunch of fresh water shrimp in there too and they all seem fine, so have done a large water change and left him where he was til tomorrow. Do people think he'll be alive or is he a goner, only had him 3 weeks after buying from HFF.

Setup is a 60 litre long tank with aquaclear on the back, room has 24hr air-con and tank stays about 18.5 deg C

[supasi]

18.5 C is very warm for Koura. Im not sure if this is cause of death , but may be a contributing factor.

[knightmarc]

really? I thought as long as it was kept under 20 deg C, will have to look into a chiller then before I get another if he hasn't made it tomorrow.

[knightmarc]

Well he is dead

Will try again once I can get another, will try to get a smaller one this time as think he was full grown.

[phoenix44]

A 60L tank is no where near big enough for a fully grown koura.

Not sure why he died though.

[Stella]

A koura found in a natural walking position but very stiff and on its side (looks rigor mortised) is usually very stressed out. They can come right from this if the reason for the stress is sorted.

Shedding is a very vulnerable time and they can get stuck, but unless you can see a split in the shell (between body and tail) this is unlikely.

I agree with Phoenix that 60L tank sounds small, but it does depend greatly on the ground area dimensions and the size of the koura. When I have seen farmed koura for sale they are pretty big.

Were you able to test the water quality? Since the koura was new to the tank it would have been going through a mini-cycle.

Any other tank mates?

[knightmarc]

He was on his back and no movement for nearly 24hrs so I'm 100% sure he was dead.

My tank is a 60 litre (600mm x 300mm x 300mm) with full lid and a aquaclear 110 filter with propeller modded to reduce flow.

Shows most of the tank, have a large fake rock with caves in it, is this ok or should I get more natural rocks, also the plants are fake silk plants

Here he is a week ago he liked the cave at the bottom the most

This is post-mortem to give an idea of his size.

His only tank mates are 20-30 fresh water shrimp which are still doing very well. I was testing the water and ammonia was up to 1.0 so I was doing daily water changes.

Food wise he got algae waffers, peas and some sinking shrimp pellets

I'd like pointers on anything I'm doing wrong to fix as I'm getting another, this time a smaller one from some one out West Auckland who has a pond full.

[bdspider]

Food wise he got algae waffers, peas and some sinking shrimp pellets

He probably would have appreciated bits of fish (like whole frozen prawns) and insects a bit more. I'm amazed he actually ate algae wafers??? Did you actually see him eating? Perhaps he was undernourished?

[knightmarc]

There were plenty of live shrimp in with him if he wanted a more meaty meal and yes he would come out and get the alge waffler. Will try the next guy with some food like you have said.

[phoenix44]

You might want to try a larger tank without a lid that keeps the heat is as well. That might help too.

[Stella]

I just remembered something. Do you use dechlorinator chemicals or any other water additives? A member here was having koura problems and apparently the dechlorinators are toxic.

Probably best to avoid any med or other chemical additives unless you have confirmed with crayfish keepers that they are ok. There is actually a roaring trade in crays overseas, just not koura, obviously.

The ground area is a little bit small in that tank for a koura of that size. I would also recommend laying that wood or rock thing on its back to create more caves for him. The more hiding places they have the happier they are. Would probably dig out new caves underneath. Crays are the most enthusiastic landscapers!

The 20-30 tank mates were probably becoming fewer over time

They love peas, eh! I am sure what you were feeding was fine. And yes, algae wafers are also appreciated by them.

Apparently koura eat a combination of vegetable and animal detritus. My understanding is that (to some extent) when they are little they need more animal, and as they get bigger this becomes a smaller proportion of their diet. Apparently the animal material is used for growth and the vegetable material is used for energy.

If anyone is interested in learning more:

http://www.informaworld.com/smpp/conten ... a920468311

http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

(if you can't access these, email me and I can send you the .pdf)

The lid of that tank will be keeping the heat in, which could be a problem over summer, but 18 degrees isn't bad, just the higher end of ok. Lids are necessary for koura, even just a decent lip all around the top. They can climb quite well or swim backwards with tail flicks, and are quite shrewd at escaping.

(This may or may not gross you out, but you can dry out and keep dead koura (or their shells). Just put them on some polystyrene and pin the legs out in a lifelike position. Obviously dead ones can get quite smelly, and cats/ants think they are great. Best done over summer when you can dry them quickly in the sun.)

[knightmarc]

Should have my new Koura on Saturday but thinking maybe I should change gravel from pebbles to a fine gravel or sand as have noticed alot of waste falls in between the larger stuff. What substrate do others use with their Koura?

[Stella]

Hmmm, good question.

Koura probe into the gravel with their front two walking legs (not the big nippers) looking for food - they can taste with the little nippers on the ends.

Large gravel = food can fall through more easily + the koura can access it more easily.

Small gravel = food can fall through less easily + the koura can not access it easily.

Sand = food can't fall through (though can get hidden) + koura can find it easily (but can't dig or landscape - natural behaviours)

Furthermore:

Shallow gravel = koura can access most of the food but worse for undergravel filters and landscaping can expose the tank base.

Deep gravel = koura can't access all the food but can do a lot more landscaping without making the tank ugly, and there are more landscaping options for you!

Also really large gravel (I am talking 5cm+ here) is horrible to gravel vac.

Just hit your local stream and poke around a bit for whatever gravel size you want and get some bigger stones for caves. It looks so natural when the gravel is not perfectly smooth and graded and the gravel and rocks match

[/long answer]

I use quite chunky deep gravel, with an undergravel filter to help speed the decomposition of waste that gets lost or gets missed by my (lazy) gravel vacuming :lol: