i would like to no wat kind of sumstrat to us on mudskippers. i would like to make it muddy but i dont no wat to use

I've never kept Mudskippers...but here are a few links that'll help you out. :D As for substrate...I'd use sand for a beach rather then mud.

http://fish.mongabay.com/species/Periophth...s_barbarus.html
http://www.aquariacentral.com/fishinfo/brackish/mudskip.htm
http://badmanstropicalfish.com/profiles/profile35.html