slayer , for some reason your question about macro options with that nice ep1[ive got one too]
for aquarium shootingdoes not have an answer option , perhaps adash or one of the other mods can fix this....


for what you want to do , on a budget, i would suggest the following

buy a legacy lens for under 20 bucks ...a 50 mm f 2 or 1.8 from one of the makers of slrs from the 70s 80s and 90s or spend a little more 40-100 us dollars on e bay  for a 50mm 1.4... konicas can be inexpensive and are very... good ...minolta, canons,, olympus nikons etc   make sure its a manual focus model with a ring for changing f stops...next you need a set of extension tubes a set of three of different sized that can be used singly or stacked is about 15 dollars

shooting with bright lights andmanually focusing moving fish is an exercise in fustration
its not an easy task for the most experenced shooter , but if you use good lights, a high f stop
like f 16 for greater dof sufficent shutter speed to stiop action and a lot of luck, youll get some shots,, shoot lots and the review to see whats sharp and useable

good luck and welcome to the forum.............other forum members , please add you thoughts tooi probably left something important out!

 

 
it should be matched to the lens.....lastly get an adapter to use that legacy 50mm lens on your ep 1 , its a hollow tube [ so are the extension tubes!]that positions the slr lens the correct distance from the ep1 sensor for correct infinity focus,its gonna cost less than 20 bucks too for most common types

a good place to get it is
"rainbow imaging" , the owner is a friend who delivers in person sometimes , hes like a hong kong dealer but shipping from queens ny but he ships worldwide im sure

tell him paul from ep1. net sent you and you hope for the best price,lol...if he not sure who YOUR TALKING ABOUT ,tell him the guy who buys the adapters at whole foods on 14 st manhattan