Maybe not yet but you will soon be way overstocked I'm afraid. Clown loaches can get over 10" long and silver sharks and common plecs about the same.
Also I'm sorry to say that two RTBS in a tank this size is likely to end in one being killed as they can get very territorial. Your LFS really shouldn't have sold you two - they must know what is likely to happen.
If you got all these fish from one store then I'd be tempted to complain about what they've sold you and take the plec, the two silver sharks and one of the RTBSs back straight away. Get a couple of Ancistrus instead of the plecs as they stay small and do a good job with algae. Explain to them also that, unless you get a bigger tank, you will be bringing 4 clown loaches back soon and also say how disgusted you are that they sold you these fish never asking what size tank you have. Sorry but this kind of thing really annoys me as they should have asked what size tank the fish were going in, they never should have sold two RT sharks at the same time (unless you went back and got another later?). This is a good lesson why you really need to do some research before buying any fish as fish stores unfortunately will often not be responsible in what they sell.