I noticed a red fish in my fishtank some days ago. That might be a theme I could serve with
The difficulty is, by adding a particular theme it's important to make sure the theme by itself is not to restrictive. This theme was not that difficut. I never manage to photograph bows flashing their racing stripes but the gudgeons were guaranteed to provide at least one good pictures. I had some other pictures from this session but chose this one since it did not require cropping.
@ Gunther, hope you get well soon. I was already worried my spam mails were the cause for the delay.
Personaly I have a rather small collection of fish and only 4 fish tanks of which 3 are occupied by PNG or australian fish/shrimp etc.
Sticking with photographing by theme would have my personal preference. How about 'portrait'.
So far I never managed a nice fish portrait so it would be a challenge for me personally
EDIT:: I would also be able to provide a picture if the topic would be 'small white thingies on the glass' or 'just chilling'