You are completely right – simpel question – not simple answer and not easy to do.
Given the difficulty we have had to actually determine what is what in your four fish, you are right, – in a cloudy tank with four scared fish it will be next to impossible to be sure that you take the right fish.
I remember in my beginning time with paroes catching them was a nightmare, – and they hide like I had never seen any fish do. You could have a 12 liter tank and think you had stripped it of everything, – leaving just a little bit of brown dust settled on the ground, maybe a few bits of leaves, – and there should be 6 fish in the tank and I could see none :blink:
They could disappear under the tiniest bit of leave or dirt and look totally invisible.
But then when you stirred them they would dart like a racket around making it so difficult. Well .. sorry 😛 ..
But – why is it then not at all that difficult for me anymore, – I must have learned some tricks, – and I will see if I can give some on to you. You sound like you have quite a lot of experience with fish and that should be helpful ..
Sometimes – quite often – I simply strip the tank, – but then my tanks now are without too much. So I can lift up the javamoss, take away the wooden piece and then thats more or less it. But often I still have leaves in there.
But the things that can be taken away easy, I will take away. Then leave the tank to settle.
But I do first try to see if I can catch the fish without doing any changes, and it really seem not so difficult :whistle:
But I do know its a matter of having done it many times. But if you have a good area up to the front glas where it is possible to get a net down thats helpful. The best way is to get the fish up towards the front glass and get the net over it there. Often the fish, when not disturbed, swim around the front glas anyway, and if you get the net down behind them, they will seek up to the frontglas, probably hiding in the corner or under some leave (so none of these at the front glass)
Then get the net over them, – so they are caught between the net and the front glass. To get them to seek inwards into the net I have learned that to annoy them with a small torch-light is helpful, they dont like the light right in their eyes.
If you take something out, like a bigger root or something, be very careful, because they can hide in these, or actually cling so tight to them that you dont see them, – they will travel right up with the root and end on the floor.