I have shopped at eah Great Barrier Reef and Reef Gallery. I thought that the advice provided when I was able to get any in either store was poor. I also thought that each store was overpriced and the health of the marine fish was questionable. I had owned a 75 gallon marine aquarium for ten years prior to relocating to Denver. I have had some fairly significant experience with marine tanks. Anyways, I stumbled upon a business named Sherman Tank Company. They are located at 7296 Federal Boulevard, Westminster, CO. The shop is always busy. Inventory turns over very quickly due to high sales. All of the employees are extremely helpful and knowledgeble. If one of the employees specializes in fresh water and you ask a question about marine that they are unable to answer, they will not provide a ration of nonsense, they will get one of their co-workers knowledgeble in marine to help you or get the answer for you. If you walk through the store and one of the employees is available, in other words, they are not busy with other customers they will ask if they can help you. The likelihood that they are not with another customer is slim, so you will probably have to go to the front of the store and wait in a short line, usually no greater than three customers deep, and ask for some help. Again, this is only because they are that busy. Lastly, they do have the best prices on aquariums supplies, food and fish that I have come across in the Denver vicinity. I have purchased a complete 125 gallon marine set up including fish from them. Currently living in my tank is a Dragon Wrasse, Yellow Tang, Majestic Angel and a Mooray Eel. All purchased at Sherman Tank.