Trouble with Notho fry

[nonamethefish]

Ok, this is the second wetting of a bag of N. kafuensis 'Kayuni' ZAM 97/9. I probably got maybe 7 or so good fry(as in not bellysliders). Now it looks like I am down to one. 3 days ago I had 5. It seemed they always died in the morning and would be floating at the surface. No outward signs that I've seen. This little one(prolly 5-6 days old) is almost the size of a grain of rice.

The water has been trying to develop an oily film but I've been removing it with waterchanges. Fry were started off with BBS. Temperature is approx 76 degrees.

Insight would be appreciated.
~Joseph

[TyroneGenade]

What are you keeping them? A tub? A tank? Are there any plants in the vessel? What about snails to eat left over bbs? Have you had a good look for velvet? When you change water do you change water with water of the same temp and parameters?

Your fry die in the morning... If you have lots of plants in the tub then it could be oxygen deprivations. If the water is very soft it could be a pH crash during the night.

Is there any filtration or aeration in the vessel they are in?

You have kafuensis... this is not an easy fish to get good hatches from as well as rear. The good news is that the eggs develop in a staggered fashion and you should have eggs left in the peat... the is provided you did not start feeding the fry over the peat in which case any uneaten bbs has probably fouled the peat and killed the eggs.

Your "oily film" worries me. This could be an oil residue contaminating the tank from some where... maybe a faulty blower? Or it is the formation of a bacterial biofilm in resonse to 1) high nutrients in the tub and 2) low oxygen in the water.

Sorry I can't be more helpful.

Regards

[nonamethefish]

Sorry forgot to mention some more specs.

The fry(well, one lonely one) is in a ten gallon tank. Some java moss and a few snails.

No aeration in the tank. I'm thinking this is probably biofilm I'm dealing with.

Barry on killitalk suspected that this was velvet since I didn't have salt in the water. I added some according to the dosage yesterday. Can't say it made things better but the lone fry is still alive. Their might be a few bellysliders around(hard to say with them)so we'll see. I suppose if I manage to raise this single one up I can see if anyone has a mate for it.

-Joseph

[TyroneGenade]

Plain salt is pretty much useless against an established velvet infection unless you are going to up the dose to 3 tea spoons per gallon which is not good.

Check your water. With so much biofilm the water cannot be 100%.

Is there any fish waste or dead brine shimp in the tank?

Is the tank fully filled?

I never put young fry in a deep tank. The newly hatched fry go from the hatching tub (now days max dept 4 cm) to a tub of the same depth. They stay there for a week and the water is slowly raised to about 7 to 10 cm while water changes continue. After the 1st week they go into a large tub so I have about 10 fry per 2 L, then they are diluted again to 5 fry/2L and so on till 1 fish/2L which seems to give OK growth. For best growth you want 1 fish/5 L it seems. Then I can bring my old inbred N. furzeri Gonarezhou up to 7-8 cm in size which is about as much as I can get out of wild stock furzeri.

Keeping the water shallow and a small volume helps the fry find food but you then also have to perform excellent quality maintenance else disease etc... gets out of hand.

Regards

[nonamethefish]

The water depth is approx 4 inches right now. I don't see any dead BBS and I did my best to remove dead fry(also got a few snails as cleaning crew). The BBS tend to move towards the corners where it is brightest and the fry thus are able to feed on them.

Edit: I just noticed that we actually have 2 free swimmers left-someone must have escaped my radar yesterday.

Would adding a corner or sponge filter be a good idea now?(fry are approx a week old and grain of rice size...seems they should be able to tolerate some gentle filtration).

[TyroneGenade]

A sponge filter supplying gentle filtration should do no further harm... Still keep up with the water changes.

Regards