ok i am tuning my coffee table into a coffe table aquarium if that makes sence i have the tank all sealed up and ready to add water to it but we want it to stick out a bit more we are putting cold water fish into it only question i have is are cold waterfish ie black google eyes and gold fish ok to have a sand base or do they require gravel

is this table with glass top? will there be constant ventilation somewhere? or have a filter? it is an idea that cropped up many times here but we would advise against this as it is impractical or unsuitable for the fish welfare. How will you feed it? you would have to lift it up every day by clearing the content on table first etc.

it is not tight against the table so there will be ventalation into the tank yes i have cut out a a4size hole on the top of the table and placed a a4 size of clear perspex into the hole wich is flush with the grove i cut out and this is the feeding hole so i do not need to clear the table. also if required i can run a internal filter into the tank not a problem.

now back to my original question are cold water fish happy with a sand base or do they prefer gravel

Some people say sand irritates their gills but others keep theirs with sand with no problems. Personally I prefer very fine pea gravel 2-3mm as they do like to rootle about in the substrate. Sand can also compact and get anaerobic patches, gravel is less likely to do this as it doesn't compact.

HTH

I would choose gravel over sand too. Less risk for the fish's gills/scales.