All beginners in aquarium husbandry often grope in the dark not knowing what fish exactly they want to have in their tank.
On seeing a small and cute suckermouth catfish in a pet-shop they don’t even have a clue that it’ll grow to be over 30 cm (12 inc) long and live over 20 years.
And this graceful oscar fish (Astronotus ocellatus) will grow to be very large and it’ll eat everything in a tank that gets into its mouth.
So, what fishes is it better to avoid at the beginning?