Dark corners

[cleo]

Hi, Have had quite a few breeding episoded and have set up a 2' tank to try my luck. Have tried a few times but the fry don't attach once they are free swimming. This lot have lasted a lot longer - 2 days and I'm hoping they will continue to do so. The only thing is that the corners of the tank are black. I have been trying to work out what to do and just thought that maybe I could use grey duct tape to cover the corner from the inside. The only thing is I'm not sure if there would be anything in the duct tape that might upset the water. If anyone has any further suggestions it would be greatly appreciated.
Also when do I need to start to feed them?
Thanks Heaps. Bev

[Ben75]

try white pvc angle , you can get it from bunnings and fix it with aquarium safe silicone to the inside edge.
regards,
Ben