probs with 6 week old juvies

for a few days now i've had 1 juvi from 30 laying on bottom of tank on his side in a corner. when other fish go near him he comes upright again and swims around but eventually goes back to this position. just tonight i observed him a little closer and noticed he is bearly breathing when on his side and the breaths he does take are very deep. i also have 2 more starting to lay on their sides on the bottom. there are no other visible signs of illness and there is plenty of airation in the tank (2 sponge filters in 150 Ltrs water)
anyone know whats going on

What are your parameters?

pH?
Ammonia?
Nitrite?
Nitrate?
Temperature?
Hmm anyone sprayed pesticides near the tank lately?

Sounds like they are gradually being suffocated to me. I would say your ammonia levels are high, which is slowly poisoning your fish :shock: !

Try a 20% WC, and add some ammo lock to the water if you have any on hand.

PH 6.6
Temp 30c
as for the rest never tested for it.

Do an immediate large waterchange Aaron.

How often have you been changing the water in the fry tank, and how much are you changing.

Six weeks is a fairly critical time for fry. You really need to know your water parameters.

I change 30Ltrs from a 150 Ltr tank everyday

unfortunetly when i got up for work this morning 1 had died. I will get an ammonia test kit after work today.
Last night i put a large dose of PRIME in tank thinking its ammonia lvls 1 has come good and the other is hanging in

Got home from work to find 2 still with this behaviour. 1 of them looks alot worse then the other its bending in the middle and looks like its in alot of pain !!!

I had the water tested and it was ammonia.

good call mcloughlin2

Ammonia is the biggest killer of young fry. They need very clean water. Lots of breeders change 50% twice a day in fry tanks, but half the volume of the tank once a day is the absolute minimum.