Dear Logan:
Yes, sir, 120 Nassarius snails are WAY too many for a 30-gallon aquarium. That’s a lot of biomass to add to a relatively small aquarium at one time, so you will need to be alert to the danger of a potential spite in the ammonia or nitrite levels in the tank. That’s the immediate danger…
The second thing to beware of is that Nassarius snails are not grazers that feed on algae, but rather, they are meat eaters that will clean up leftover frozen Mysis. But there will not be enough leftover frozen Mysis from the ponies in a 30-gallon setup at mealtime to sustain 120 Nassarius snails, so there is a danger that they will begin dying off due to starvation.
Of course, you could attempt to compensate by feeding additional frozen Mysis just for the snails once the seahorses have had their fill, but all of that extra frozen Mysis would again increase the risk of a dangerous spike in the ammonia or nitrate levels following a heavy feeding. So it’s going to be very tricky for you to keep all 120 snails adequately fed without overdoing it and triggering a spike in nitrogenous wastes. That would be a delicate balance to try to maintain for any significant period.
In short, Logan, you don’t want to maintain more than 10-12 Nassarius snails in your 30-gallon seahorse tank for any length of time, so you should make plans to re-home 100+ Nassarius snails as soon as possible. Perhaps your local fish store would be happy to take the surplus off your hands since their regular supplier has not been able to get Nassarius for them recently.
If not, you may have friends with saltwater aquariums who would love to get some free Nassarius snails, so maybe you can disperse many of them to your fellow hobbyists.
Otherwise, you’ll have to set up some sort of additional aquarium to house the excess Nassarius so that they don’t become a potential risk to your seahorses in the 30 gallon setup. Nassarius snails like to bury in the sand, so this extra tank should have an inch or two of fine sand (preferably live sand, in my opinion) that they can burrow into; and this new tank will also need to have an efficient biofilter to sustain that many snails indefinitely. You can just feed the snail tank with a decent amount of frozen Mysis daily, and hopefully everything will go smoothly.
Good luck!
Respectfully,
Pete Giwojna, Ocean Rider Tech Support
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
