Unwanted fish

Hi Guys,
Right lets start from the beginning, set up a new marine tank around 2 months ago, have been in the hobby for a while now and this would be my third marine tank.

I have recently added a few fish, but here is the problem its a 100 gallon tank and as always want to choose my fish very carefully. Answered the door one day and there was my girlfriend standing there was what i can only describe as the ugliest fish she could find in the shop (no fault of her own). I have tried to get the name but its not even on the web. As a true gentleman i didnt tell her i didnt want it. Added the kretin to my tank, after a couple of sleepless night i have decided to take it back to the store. Have tried netting it but no luck, i have around 40 lbs of Liverock so you can imagine how hard it is to catch it.
Please help! any suggestions would be greatly appreciated.

I live in Dubai United Arab Emirates, i think its just a reqular sea fish they must have caught with a sock. But it resembles a squirrel fish if that helps. I have had previous trouble with damsels and had to pretty much gut the tank to get those guys out, i dont want to have to do that again.

Thanks for the suggestion but please eloborate on this food basket. Failing this are there any other possible suggestions within reason. It has also been suggested that i try fish him out with a tiny hook and line. Thats the last option as its very cruel, you are prob aware that fish know whats going on, the other fish are all about and swimming but that twat just swims behind the rock shelf.

I dont want him in my tank. Cheers for the immediate replies.

cheers buddy, is this a tried and tested method. Knowing my luck all the other fish will have a rest in the basket while that guy snacks from the food the night before. you prob think im a dumbass but how do i position this basket. need to get all details on this so i ensure the capture of this sewage going fish.

Thanks again and greatly appreciated as i am fed up of him

Thanks again, will give that a shot tonight and post tomorrow to see if it works.