Hi to all got my first Oscar and have a temp question

[Barend]

Hi, got my first oscar and have a 100L tank and only one oscar in it. Water ph 7.6, gh 16, kh 10, n 0 and n0, tank temp is 26, so the problem is when the temperature is 26 he is only lying on the bottom and is swimming now.

Generally when I up the temperature to 27 - 28, he is more active and is swimming a lot, looks healthy. Also so I don't understand when dai says an oscar temp have to be between 25 - 27. Thanks for the time.

 

[Delapool]

Do you think the temperature is the same all over the tank? ie is the temp reading accurate or does 26 mean it is colder at tank bottom or something.