Stocking New Tank

I have just cycled my 120 Gallon /540 litre and was wondering what to add to my stock being transferred from my 120 litre
Stock will be 10 Black Skirt Tetra
10 Gold Barb
6 Albino Cory
2 Bristle nose plec
5 Harlequin Barb
2 Clown Loach

I agree with Andy. With a huge tank like that the first thing is to get more of some of the fish you already have. So not only more clown loaches but a few more cories of the same species and a few more harlequins. (Query, you typed harlequin barb, are they harlequin rasboras or a barb I haven't heard of?)
Having got 14 espe's rasboras and 18 ricefish, I would suggest getting 15 harlequins, gold barbs and tetras.

As for clown loaches, it is safer to try and find more of roughly the same size as the ones you have now. If yours are bigger than those in shops, try looking for someone wanting to rehome some. You need at least 6.
However there is one proviso. Clown loaches need a tank with a footprint no smaller than 180 x 60 cm (71 x 24 inches). If your new tank is tall with a smallish footprint for the volume, I would think seriously about rehoming the loaches.
The website aquarist classifieds is the first place to look.


Increasing the tetras, barbs and harlequins to 15 each, the cories to 10 and the loaches to 6 puts you at 40% stocked. But the community creator does warn against mixing the loaches with harlequins and the tetras.
And I've had to enter 20 panda cories instead of 15 albinos as albinos are not in the fish profiles - or indeed any of the 2 inch cories. And black skirt tetras are in the profiles under their other name of black widow tetra.


Living in Spennymoor, you have soft water so the fish you already have are good. You need to avoid hard water fish, which are mainly fish like livebearers and Rift Lake cichlids. But that leaves a huge number of fish to chose from.
Is your preference to have a tank full of small fish plus the clown loaches, or a smaller number of small fish plus a few larger ones? You can't go too big or your current fish would end up as lunch, but there are a lot of medium sized fish that would work. The main type of fish to avoid are those that live on the bottom of the tank as that will be a bit crowded with clown loaches.