Royal Gramma Missing Tail


New member

I purchased a Royal Gramma about 2 weeks ago. All was healthy and the fish was doing well. She found a hiding spot in my live rock and her tail sticks out a little when she sleeps.

The past 2 days I noticed she wasn't coming out as often. Only when I put food in the tank does she come out of hiding. I noticed the last 2 days her tail is missing. Could this be a disease or something bit off her tail?

Pictures included. Any ideas? Thank you!!!

Details about my tank:

1. Aquarium is 3 months old. My old tank leaked and I moved live sand/rock into new aquarium. Aquarium is a 40G breeder, 20 gallon sump.

2. Ammonia is 0, Nitrite is 0, Nitrate is 0, PH is 7.8, Salinity 1.023. I had local pet store check and they agreed all my readings were correct. They couldn't believe my Nitrates were so low. I did catch an ammonia spike in my testing about 1.5 months ago. This would have been 1.5 months after I moved into the new 40G breeder tank.

3. SG is 1.023 measured with a refractometer

4. This is the last fish added to the aquarium

5. Fish was not quarantined. I did the drip method for 4 hours until the SG matched from the pet store. Pet store SG was ~1.021 my tank was high at 1.025. I made sure the drip container SG matched my tank before placing the Royal Gramma in the tank. That is why the drip method took 4 hours.

6. No medication used. I have small hermits, snails, and coral in my display tank

7. I used calibration fluid of 51.3 from my pinpoint marine to calibrate my refractometer.

8. Beside the fish's tail all looks healthy.

9. The Royal Gramma always comes out of hiding to eat. The fish is eating each time. I'm feeding frozen mysis, brine, some flake food, and freeze dried mysis. The fish swims around great when eating. Then it goes back to hiding always in the same spots in the live rock.

10. The Royal Gramma eats all the fish foods I have provided. Frozen mysis, brine, flake food, freeze dried msysis. I feed once per day.

11. Tank Stock: 1 yellow watchman goby(very healthy from old tank), 10 mix of blue and red hermit crabs, 1 nassarius snail, 1 tiger pistol shrimp(very small lives on other side of tank), Coral

Thank you, I really appreciate the help!


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Michael Hoaster

Registered Seaweedist
Premium Member
It's possible the established watchman goby, got nippy with the gramma, since it was 'new'. In this day and age, quarantine is very important. Get a quarantine tank.

If the fish is healthy, the tail will grow back pretty quickly.


New member
Thank you

Thank you

Thank you for the reply.

I will try to setup a sponge filter in my sump to let bacteria develop. Then I will setup a 10 gallon QT using the established sponge filter. I don't plan on getting fish larger than 3". I will do more research on QT tanks.

My problem is having the space to leave a QT tank permanently setup and making sure I don't have an ammonia spike when using the QT.

If I ever used medication in the QT I would purchase a new sponge filter and seed the bacteria from my sump.

I hope the problem is only the watchman goby or hermits and the royal gramma recovers.

I'm going to try feeding twice a day to reduce aggression in the tank. I only feed once a day now, to keep undesired nutrients in the tank. I think it is why my nitrates have remained so low.

Thanks again!

Michael Hoaster

Registered Seaweedist
Premium Member
QTs don't need to be permanently setup. In fact, it's best to tear them down after each treatment and sterilize with bleach everything wet. Ammonia won't spike for a week or two. Then you can do a water change, or use one of the many ammonia eliminator potions available. To help with biological filtration, scoop a tablespoon of sand from your display and add it to your QT. Also add a macro algae plant, which sucks up ammonia, and provides comforting cover for shell-shocked new fish. And as you mentioned, keeping a sponge filter in the sump until needed works great.

Feeding twice a day is a good idea. Hungry fish get mean. I hope your gramma recovers too. That it comes out to eat is a good sign.