Backyard Aquaponics
A place to discuss aquaponics

Does anyone have any good ideas on the way to grade my fish, I have 23 trout ranging from about 15 to 25cm.
I have twin ibc fish tanks so I want to put the smaller half in one by themselves so they can get a better share of the food.
I'm just looking for others experiences or methods in this.
Thanks in advance for any help or advice

Well i haven't graded my trout so I can't help you with the practicalities, but I think it would be a good idea because I noticed when I gutted 5 of them this weekend that the biggest two had stuffed their guts full of pellets while the smaller three had hardly any or none. So while I always knew there was a "pecking order" I didn't fully appreciate the extent to which the biggest trout would dominate the food supply.

Yeah I was watching mine feed the other day, watching all these "monster" fish burst out of the water smashing the pellets which were all gone in about 30 seconds so I thought I'd chuck some more in just to see how much they'd eat and once all the bigguns had finished the little tiny blighters started coming up and they looked tiny compared to the others, which was when I decided it was time.

at such a small scale you have 2 options.
1. sort every single fish by measuring length and/or weight.
2. make something like this by hand: https://freshbydesign.com.au/products/box-grader or buy one.. but they are stupidly expensive.

by the time you started setting up any sort of grading system you could have sorted 20odd fish by eye. The hardest thing would be doing so as to not double handle them. Net them all into a bucket and then sort them out big and small into the two tanks, should take 5mins max.

Be careful catching, grading or handling trout. They have a tendancy to stress and exhaust which sometimes pushes them over the edge.

Cool thanks for the advice, gm that sure is alot of money for a box with holes in it.
Charlie do you think if I moved them all into a big tub and upped the salt a fair bit and graded them from there back into the two tanks, would the salt help with the stress?

i guess the stress must be relative because compared to salmon trout are hardy as anything and we struggle to kill them at work, you can have a trout flipping around in the dirt for 5 minutes and the bastards will still come back. They are also blessed with not suffering from many diseases at all so even if they do get stressed it never results in a disease outbreak( in tassie where we dont get Ich.) unlike salmon that will usually fall ill with yersiniosis if you look at them sideways.

going from fresh to salt then back to fresh would stress them more than just having fresh at all stages. The whole process should literally take you less than 5 minutes, they wont even know what has hit them.

If you want to be really pedantic you can put clove oil in your big tub and knock them out for sorting, will technically make the whole experience less stressful for them but comes with the inherent danger of killing them if done wrong(small risk).

Cool thanks mate.
Guess ill just have to have a crack.
Ill get the boss to take some pics n let you all know how it goes.