125g stocking question

[ErikH]

I have two extremely dominant yellow tangs. They gang up on everything. I added a purple tang, which is small, at night and they are all buddy buddy. I recommend staying away from angels or any fish that may be a PITA later. If you have ever had to break a tank down over a four dollar fish, you know what I'm talking about! The trick with relying on natural filtration is to add fish singly, testing water quality over many months to achieve equilibrium. Always undershoot your bioload also because fish do grow. Try not to add any fish that will eat pods, bristleworms, or spaghetti worms as they can be very beneficial in the breakdown of excess foods and detritus which will be crucial in a sumpless, skimmerless, setup. If possible try to incorporate the use of asthetically pleasing macro algaes into your display which will thrive on the excess nutirents and allow for means of export out of your tank.

Edit: time is your best friend here. Try and keep the tank fishless for as long as possible and try to build up the tanks biodiversity before adding ANY fish. Also mind your fish list as adding them all at the same time will add incredible stress to your system unless they are all very small at time of introduction.