Flatfish ID

maybe Hippoglossus hippoglossus?

@Kakapo seems too small to be the atlantic halibut (was about 20cm tops), JAZA has no records of the halibut either.

Plaice

@RatioTile Yeah, that's what I thought. Wasn't 100% sure though.

Was it no longer signed? There was a sign for this tank when I went.

@RatioTile There was a sign I believe, but I didn't take a picture of it. I thought I remembered that it said plaice, but with no pic I couldn't be sure. It didn't say what species it was, but it most resembles the scale-eye plaice, as it had faint orange spots and distinct corners on the fins around the edge. However, there are no records of that species on JAZA.

When I went they were buried in sand, so I couldn’t get a good look at them besides their faces.

@RatioTile When I was there they were all extremely active, even the ones on the bottom weren't buried and moving around a lot. Very unusual for flatfish, but was great for photos.

Could also have been the European Plaice (Pleuronectes platessa), which also has the faint orange spots. IIRC the tank was the North Sea tank, which makes sense for the European Plaice, they are found there.

Bingo! I think that's the one! The JAZA listings show one holding of the species, at Tokyo Sea Life Park.