Watchman Goby Regrets: What I saw Horrified Me

[NanoReefer2025]

Hello reefers,
I have some saddening news, for me anyway. Yesterday, I got a watchman goby from my LFS for my 25 gallon AIO that I set up last November. Acclimation went smooth enough. I added a little bit of tank water every five minutes for 45 minutes in all. After that it disappeared, but I wasn’t too concerned because I read that this is normal. Just 30 ish minutes ago, I checked on the tank and what I saw was horrific. The once-bright yellow goby was a sickly gray, its fins tattered, and my scarlet hermit crab enjoying its remains. Sorry, I don’t have any good pictures. I am not sure entirely what happened. I figured that perhaps the hermit crab was not getting enough food and cornered the goby in the burrow that it was digging. Or maybe the goby simply wasn’t strong enough to survive the stresses of moving to a new tank. I am very new in the hobby, so I could use any advice for avoiding this in the future.

[paulsz]

In my experience, the fish was already stressed and only got more stressed when you bought it. Not your fault, especially if you did acclimate it. 

 

It's happened to be before with a blue chromis. Bought it one night after work and it was dead the next morning. 

 

The scarlet hermit ate it after it had died. 

 

It sucks, but don't feel like you did something bad. This kind of stuff happens.

 

Keep acclimating the way you acclimated this fish. 

[NanoReefer2025]

1 hour ago, paulsz said:

In my experience, the fish was already stressed and only got more stressed when you bought it. Not your fault, especially if you did acclimate it. 

 

It's happened to be before with a blue chromis. Bought it one night after work and it was dead the next morning. 

 

The scarlet hermit ate it after it had died. 

 

It sucks, but don't feel like you did something bad. This kind of stuff happens.

 

Keep acclimating the way you acclimated this fish. 

Thanks for the reply. I will keep this in mind, but I still won’t entirely ditch the idea that I might have done something wrong. I learn more by experience than research honestly. Don’t get me wrong, I did months of research before even buying the tank. The information is all in my head. It’s the implementation of the research that I have a problem with.

[Clown79]

Hermits don't attack fish, sounds like the goby died and the hermit is cleaning up which is their job.

 

Most don't recommend acclimating fish besides floating the bag in the tank to reach correct temp.

 

This is because the longer the fish sits in a bag, the more ammonia is produced causing more issues than just temp acclimating and adding it to the tank.

[paulsz]

25 minutes ago, Clown79 said:

This is because the longer the fish sits in a bag, the more ammonia is produced causing more issues than just temp acclimating and adding it to the tank.

would this be an issue if buying from the LFS? like total of 1.5 hours between bagging the fish and finishing acclimation?

[mcarroll]

It's actually better in some cases to just add the fish to the tank (WT or display, whatever you're doing), ideally with a short freshwater dip (~ 1-5 minutes) on the way there if you have any question about passing on parasites.

 

Longer acclimations have to be closely managed and can easily go wrong.  

 

For example: Adding tank water to the bad water can raise the pH toward 8.2 which can skyrocket the percentage of toxic ammonia (NH₃) in the water with the fish. ☠️

 

So on average, a short acclimation or no acclimation is actually better....and you handle the exceptions (eg. delayed flights, overpacked bags, et al) as exceptions.

 

I strongly (and regularly) recommend reading Sustainable Aquatics' white paper on acclimation.  

 

**If** you're going to do an extended acclimation, know why and how or you can damage your fish or even kill them in the process.  

 

Sustainable Aquatics covers the topic very completely.  👍

 

It's also well-covered in Martin Moe's Marine Aquarium Handbook starting on p.192 in the section on Introducing New Fish.

 

In a nutshell...

 

Lower temperature and lower pH in the bag water actually make the bag water safer for the fish because ammonia becomes much less toxic under those conditions.  

 

Bringing fish out of those high-ammonia, low-pH conditions with maximum success is where Sustainable's guide comes in.  (We should almost never need to do this with locally purchased fish, and only rarely with online purchases.)