How many berghia do I need?
Enter your tank size and how many aiptasia you can see. The calculator gives you a starting number based on common reef-keeping guidance.
How we came up with these numbers
Our own 16 gallon cleared up with four berghia, but that's one small tank, and we didn't want to build a calculator on a single experience. Instead we looked at the guidance reefers have been sharing for years and found where it agrees. The ranges were pretty consistent:
| Aiptasia you can see | Berghia per gallon | Minimum |
|---|---|---|
| Just a few (under 10) | About 1 per 20 gallons | 3 |
| A bunch (10 to 50) | About 1 per 15 gallons | 4 |
| Everywhere (50+) | About 1 per 10 gallons | 6 |
We recommend at least three. Part of the reason is that berghia are hermaphrodites and need a partner to breed, and a group gives them a better chance of finding each other in a big tank.
A few things that change the number
- Lots of rockwork. More hiding spots means more aiptasia you can't see. If your tank is packed with rock, consider going one level up.
- Aiptasia in your sump. Berghia can only eat what they can reach, so count the sump water in your total and expect some to end up down there.
- Fish or inverts that might snack on them. Some fish and shrimp will pick at nudibranchs. If you're not sure about your tankmates, a couple of extra berghia is cheap insurance.
How long it takes
It depends a lot on how many aiptasia you have. Our small tank cleared in about a week, but for a bigger or more crowded tank, expect anywhere from a few weeks to a few months. The best way to tell they're working is to watch the aiptasia, not the berghia (they hide). We wrote about that here: I added berghia and now I can't find them.
Still deciding whether berghia are right for you? Read how to get rid of aiptasia (what we tried, what we skipped, and what worked).