>>50982715In fact, the fish in that episode was a mistake by the animators, they were commissioned to create a scene with an aquarium in the background, but since they had no reference, they only drew a generic aquarium, this was clarified by director Shudo.
It was not given much importance because at that time it was not well structured how that world would be managed, in fact it was only planned that the series would not go beyond the Kanto league, then pokemania came to America and the rest is history.
These types of errors continued, but were becoming more rare as TPC gave greater importance to promoting pokemon, for example before human characters could use a generic animal costume for some comic contribution (Ash dressed as a cow), now even costumes are substituted with pokemon costumes.
I think the company realized that it was more profitable to use any excuse to sell pokemon, so screen time that a generic lion would occupy, better occupy a Pyroar or a Luxray so that some child wants merchandise from these, an episode focused on a farm, promotes Miltank, Tauros, Mudbray, Wooloo and so on, let's remember that anime is a great commercial.
