To answer your indirect question, You might want to reconsider the five gallon tank size. Sea horses are delicate, and it’s easier to maintain stable aquarium levels with a larger tank. The website I link to below says that a twenty gallon tank with live rock in it has worked better for them and not only do their seahorses stay alive, they also breed.

Here is the website. It talks about dwarf seahorse keeping and all of the supplies you will need to buy to successfully keep them. For some of the products, it even links you to the page where you can buy them cheapest. http://home.pacbell.net/powerfx/html/setupdetail.htm There are a lot of good pictures on that website, too. Good luck with your seahorses and don’t forget to cycle your tank before you put them in.

Update: After doing more research, I encountered a website that encourages you to keep your seahorses in smaller containers, not large ones. Website: http://www.syngnathid.org/articles/dwarfKeeping.html I think that this person is genuinely trying to help you with this advice, but that the first website I listed was better because in my own experience larger less stocked tanks are stabler than smaller overstocked tanks. This is the person from the first website’s reasoning for using a twenty gallon tank instead of a small bowl:

"I also added larger Cell-Pore sculpted rocks to the main tank for added bacteria colonies. This is almost over-kill for the 20-gallon tank but it will definitely be very stable with the included power head for proper water circulation.. Currently, I am preparing to lace the 20 gallon tank with some Amphipods (Grammarus) and algae from my six gallon. Hopefully, the tank will fill up with algae and Amphipods (Grammarus), which will provide a natural live food source for my horses. I think the trick to my method will be in keeping the Amphipods (Grammarus) one step ahead of the horses. That is why I am using such a large tank for dwarf horses. My theory is that if I place a reasonable number of horses in the tank (6-8) then they won’t be able to eat the Amphipods (Grammarus) down. The tank is so large that the Amphipods (Grammarus) will be able to reproduce and fill the tank at a rate that will allow constant grazing for the horses. If this works out well then only an occasional treat of brine shrimp will be required. I will also keep my six-gallon working as it is now – for the Amphipods (Grammarus) in case I need more for the horses.

I know many people recommend small tanks for the dwarfs for fear that their food will dissipate in the tank and be hard to find for the dwarfs. I think this only applies when the tank is relatively empty of food and then the food is added a couple of times throughout the day. Then it stands to reasons that the food would dissipate throughout the tank. But in nature the horses are constantly grazing the grass beds looking for the small creatures that live within the green algae leaves. I am trying to recreate this and hopefully the amount of Amphipods (Grammarus) will be large enough to provide the desired effect. Also, I must mention that I am planning to feed the Amphipods (Grammarus) daily with an invertebrate particle liquid mix. I will squirt a small amount in the tank every day. With the six gallon I used yeast, and fish fry liquid food with great success so I think the only think that is important is to feed the Amphipods (Grammarus) with health food so that the horses will get the nutrients second hand."