I haven't explored all the places mentioned here. Nor do I intend to evaluate individual shops. Generally speaking, aquarium shops in Dubai and nearby places can provide you with a variety of tanks and fish. But when it comes to plants and aquascaping material, you may face difficulties. Staff in most of the shops cannot identify plant species, do not have much in stock except some pond weed and fanworts and a few bog wood. You might better forget CO2 supplied tanks and plant carpeted substrate.
For a beginner, I would strongly propose a visit to as many shops as you can for a week or so before buying anything so that you can compare options, availability, cost, hygiene and plan and budget a tank. Otherwise, odds are that you may wind up with a tank you did not envision.
Shops I know of, that supplies aquarium products are listed below:
1. Pet Zone has three branches- Next to Al Mazaya Center on Sheikh Zayed Road, Opposite to Lulu Hypermarket in Barsha and opposite to Hilton in Marina Walk.
2. Pet Corner in Green Community- interchange #7 , Sheikh Zayed Road (after Media and Internet City, before JAFZA) - I havent been to this place yet.
3. Top Pin and some nearby Chinese shops in I-Zone, Dragon Mart at International City, Hatta- Al Ain Highway- mostly equipment and tank at budget prices though you can buy fish also.
4. Creatures Oasis Satwa. Google dug it out. I havent been there.
5. World of Fishes Karama . There is also another shop next to Sunrise Supermarket in Karama
6. Shops at Animal Market, Near Sharjah fish market, Rolla Road, Sharjah. There are dozens of shops in this area.
7. Nature Beauty, Al Qusais Sheikh Colony, behind new metro station. The florist in Lulu Hypermarket Qusais also stocks some fish tank and limited supply of fish and equipment.
8. There is one in Bin Soughat Center, Airport Road, Rashidiya.
I will edit the post and add to the list when I discover a new place.
Few shopping tips:
Most of the places keep fish in reasonably good condition, but some places also keep birds mammals and reptiles in tiny cages, sometimes even with no place to move around.
Make up your mind on what you are looking for, in terms of species, size, health, color, brands, whatever you can think of. Sales personnel are employed to sell, period. They will try to make you buy what they have, which may not be what you want.
If you are buying live plants, snail treat them and wash them in a weak potassium permanganate solution before planting them in your tank. Snails and snail eggs come free with most of the plant purchases from almost anywhere. Once they get into your tank you may have a real tough time eliminating them and snail killers are too harsh on fish, biological traps may not work effectively and you may wind up buying loaches that were originally not planned to be part of the community.
Most of the shops does not have any standard price list- try bargaining and ask for quantity discounts- you may save substantially.
Ask for home delivery if you are buying tanks- chances are that you may get it free of cost.
Do not buy fish unless you know them, their feeding habits, water condition requirement, social behaviour, adult size. Buy fish that appear healthy, showing their natural swimming and schooling behaviour and kept in hygienic tanks.
Look for branded equipment and products. You may not have many options, but you can easily find Sera and Tetra products in almost every store.
Most of the sales personnel except in one or two stores do not speak much English or Arabic. If you can take a Hindi/ Urdu speaking friend along, you should be able to communicate better.
None of the shops I visited so far has a return/ guarantee system. Inspect thoroughly before you buy anything.