Backyard Aquaponics
A place to discuss aquaponics

Has anyone had any experience with this product? Having had the odd trout die following harvesting (the ones left in the tank not the ones caught!!) and a few comments here about the stress on the fish when harvesting, I thought I would look into using something like this.

AQUI-S is the approved anaesthetic for aquaculture use... for use in grading, transport, and harvesting...

It's clove oil...as has been often discussed....

Yeah Rupe and I have had a few discussions on clove oil in the past.

viewtopic.php?f=25&t=3407&p=230364&hilit=clove+oil#p230364

Marc if your Trout are dying when you are harvesting them I can assure you its not thru stress but a lack of DO. When a trout expends lots of energy when trying to avoid being caught your water must have maximum DO levels for them to fully recover. I dont think its necessary to be throwing Clove Oil in your system or Aqui-s for that matter just to harvest a few fish. If you want to harvest selectively just drop the water level in your tank and it should be easy enough to catch the ones you want.

... agreed...

And the DO stress is a good point..

perhaps it is disolved oxygen but with 2 x 20 cm air stones running 24-7 and about 25l/min air pump and a 15 min on off cycle and several periods of constant flood after feeding, I doubt i could get much more o2 in the water. Also water temps have not gone above 16c. I had heard that others had fish die when they harvested and assumed mine also died from the stress.

I think your idea of dropping the water right down to catch the ones you want to minimise their hooning around is a good idea, thanks Gavin.

interestingly it was the smaller fish (600-700gms non obese) that karked it not the biggest.

In my experience trout dont stress much from being caught if it dosent involve a chase. You can usually net a trout out of the tank and then return it to the tank throw in some pellets and it will feed straight away. A stressed fish wont do that, it will sulk down the bottom of the tank for a day or two.
When you chase trout around the tank with the net they expend a lot of energy in trying to escape which results in a build up of lactic acid in the body, the only way they can remove this is to move large amounts of oxygen across the gills in an effort to repay the oxygen debt. When a fisherman catches a trout in a flowing river he can hold the fish into the current and let the water flow through the gills, the fish quickly recover and then swim off. When you catch a fish in a lake its a different story and unless you move the fish back and forwards through the water to get the oxygenated water flowing across the gills the fish may die if it is truly exhausted.
The reason the smaller fish died is because they dont have the stamina of the larger fish and were obviously tired out to the point of exhaustion and due to lack of available oxygen moving across the gills were unable to rid the body of the build up in lactic acid. If after chasing fish around a tank you see them struggling you can hold them above an airstone and rock them back and forth and you will see that they will fully recover.

Mark, your trout are probably dieing from obesity

.... yeah they should be easy to catch... if your net's heavy duty enough...

Thanks Gavin that makes so much sense. I really appreciate your tme to explain the ins and outs of why it happens. I will harvest much differently now


thanks to Mantis and Rupert who are only being rude and hurting the trout's feelings . It is not fair that they (the trout not Mantis and Rupert ) are horizontally challenged. I really do have normal shaped trout and will post a picture to prove it Imagine how much fatter they would have been if I have fed them as much as they would eat in 5 mins whenever they were hungry

I knew I shouldnt have had a go at your fish Marc. Carma gave me a small silver swimming sideways with discolouring on his side tonight. I donged him on the head and gave him to the chooks.