I have set up a new cube, 40x40x40cm, 64 litres, as a way to remove Beckford's pencilfish from my main tank, where their aggression was disruptive – the Cory and peacock goby held a day long party now that they are gone. I only have 4 pencilfish, one macho M terror and (I think) 2 pale bullied M, with one F (or is it 3 F). I was planning to buy 10 F to see if that would settle them, or him. Since they moved in the M has the run of the tank and the others hide behind an Indian Almond leaf. I'm having some trouble finding a place that will sell only F pencilfish. I'm also wondering if a cube of 40cm is large enough? I am OK to not put anything else in except the max. 14 pencilfish. Possibly some Pygmy Cory if the tank does well and I feel the pencils would leave them alone, but I realise it would be pushing the stocking envelope. My real question is: I need to know that getting so many F will calm the macho terror, as that kind of behaviour in a Nano cube is cruel to the F. I'm also wondering about giving up and getting rid of all of them, as the cube could be used for something hassle free. As I've noted elsewhere, Beckford's are not peaceful, or certainly not in my 106 litre tank, which was well planted. The cube will be well planted, but isn't yet – I just needed to get them out asap. I doubt a cube of this size can ever really offer a series of territories. I have no other tanks that are suitable. They are beautiful fish, but the F and pale M are getting run ragged. I'd happily give them free to anyone in Scotland (I'm in Edinburgh) who can collect, and get something small and placid. Any advice? I am worried that adding more fish isn;t going to solve the problem.