What Could I Do ?

[Peggers]

Microgeophagus ramirezi require warmer water from what I've read about them, most corries aren't suited to these temps but there 1 that is often recommended but I can't remember which. Bolivian rams (Microgeophagus altispinosa) are said to be hardier and don't require the same temps.

 

[arobinson1984]

Definately no to the blue rams, they require a higher temp of 28-32 celcius.

Peggers, sterbai corys are good in warmer waters

You'd probably be ok with a pair of bolivian rams depending on how many fish you already have in the tank? A pair of bolivians should really have a min of 20 gal and yours is 18 gal so its pushing it but if the stocking is currently light then you should be ok.

Andy