Backyard Aquaponics
A place to discuss aquaponics

I have a question about trout behaviour, do other peoples trout play at the surface all the time? For a while now my trout seem to be spending a lot of time at the surface, I am beginning to wonder if oxygen is a problem. There are 30 trout (about 600g) in 1600L water, I turn the water over about 1.5 times an hour and have 30L/min air going into the tank. They seem very active and jump then dive when you come up to them but pretty soon they are near the surface again.

water quality
pH 6.5
ammonia 0.25
nitrites 0.25
nitrates 40
temp 17c

salt ? have not salted in a while so I have just added 1ppt

They seem well enough, I just have not been aware of this behaviour before and they are not feeding as aggressively as they used to. Any thoughts?

Mine are at the top to they are feeding well
Theres plenty of oxygen in there

yes mine are at the top of the tank and having a hell of a time.
Jim.

novaris you are lucky your temp is 19 mine hit 25 over the weekend and i've pulled up 30 dead trout.not happy but i should have harvested them all two weeks ago.trying to get that last bit of growth was a big mistake, on the bright side i've got 50 in the freezer and learnt a valuable lesson, so i'm just warning you to watch your temps. drew

Hey Drew sorry to hear about your losses Thanks for the warning but my system is designed to carry the trout all year - though I still need be careful. Thankfully it looks like my trout are just having a party

Drew, if your trout are dead at 25, you are lacking airation. WA Trout go to 26+ without any fatalities. Mine have been there a couple of times in the last month. Unless your thermometer was reading low of course.

Novaris - Yeah, they just play at the top quite happy - they are actually looking for food, if a fly flies over the top of the tank you get about 10 Trout jumping at it. Usually results in 1 or 2 ending up on the ground

If they have gone off the food its a sure sign that the DO levels are around 5ppm or lower. Try putting another airstone in the tank and see if their behavior changes back to normal.

Just to be sure I added another 60L/min more air for 3 hrs, no change in behaviour so O2 is obviously not a problem. I guess they really are playing. Worst part is the missus has taken to watching them if I am not careful she will treat them like pets and I wont be able to eat em .

Good to know who wear the pants:)

I'm the BOSS at my house .....,, because my wife said i can be:)

[/quote]Just to be sure I added another 60L/min more air for 3 hrs, no change in behaviour so O2 is obviously not a problem.[/quote]

I wouldnt expect a change with just 3 hours trial. Leave it running for 24hrs and then see if there is any difference. I had the same thing happen here a few days ago in one of my tanks. I have a DO meter though so after seeing signs similar to what you described I checked the DO and sure enough it was too low. I have since added more air and fish now back to normal. It was the next day before I noticed the behavior change though.

hmm not so obvious

After 24+ hours of huge quantity of air there is no difference in behaviour, well till I netted a couple to eat that made them duck for cover but now they're back to playing at the top.

So, it didnt make any difference to the way they fed then?? At water temps like what you have they should be feeding like crazy!