pair not happy in new tank

[Escher]

I have moved a confirmed pair of adult diamonds in a new breeding tank: THEY DON"T LIKE IT & they don't seem to eat. It's the same water, just a much smaller tank (a 4ft with a partition in the middle instead of a 7x2x2). They've been in there for just over a week now.
Any suggestions? :?: :?: :?:

[scott bowler]

hey Escher have you tested all the water the may be some changes .and what do you have in the tank with them eg a sponge filter or just air stone, ?

[the german]

what material is the divider?
they come out of a planted tank?

[Escher]

80% of the water came from the original tank, so I was not expecting a great difference (nonetheless I did the usual climatisation). Both tanks are bare bottoms. There is a sponge filter in both. In the breeding tank is only missing a potted plant.
I made the partition from a flyscreen material (aluminium frame, nylon screen).

[the german]

did you use any glue or silicon for the divider?
aluminium you say,whats the ph in the tank,aluminium is very sensitiv with acid,rust very fast.

michael