Rostratus question

[Danzhaley]

I have got 2 rostratus and not sure of if there male or female. The biggest one is about 3 ½ inch and smaller one about 3 inch I had them in a 350 litre corner tank but have just moved them both into a 450 litre Juwel Rio. The new tank has a blue light and I have noticed blue on both the face of the rostratus could this mean they are both male or is it just the blue light? I dont think the females show any colour apart from there black spots.

[OinKY]

If talking Fossichromis rostratus...well,you've got a while to wait.
The males aren't sexually mature until a good size (well past the 3.5" currently) and subdominant males won't color up until that time either...usually two years down the road. They need a lot of room too as they are 10+" adults and won't spawn until almost 8".By then they can play Hell on stocking with anything else (and needs a 100+g)...and add in that they are active piscivores.
This isn't a "rock-dweller"...it's open-water predator that also sifts a lot of sand.Also known to hurt itself trying to dive into the substrate when frightened.

Got any pics handy ? That'd help a bit,but still no guarantees on sexing them.