Assessors, both Blue and Yellow

[rollermonkey]

I have been looking for information on these (Assessor flavissimus and Assessor macneilli) everywhere, and I keep coming up with conflicting information.

Are they peaceful or semi-agressive?

Some books say very shy and timid, some say they are territorial bullies. Websites vary, some even say both in the same write-up.

I want to put one in my 29g cube, and since they are expensive and fairly uncommon, I want to get it in the right order to avoid problems.

It's either going to be first or last based on my other planned fish, based on what I've read, but that's a pretty important distinction.

A little help?

 

[andy13]

I put a yellow in my tank 8 weeks ago and have only seen him once. That was last week just before the lights came on . So I would say very very shy

 

[fishnerd]

Very peaceful, never has seen aggression against the many small fish that my blue or yellow are being housed with. Their personality are like firefishes/dartfishes, HTH

Bryan

 

[eatbreakfast]

Once an individual becomes established, which may take many months, he will defend his territory against certain fish. In my tank my yellow assessor has chased a small ecsenius blenny and a firefish. The chase was very brief, no harm done, and settled down after the blenny and firefish had been there for a week. Other than those occurances my assessor has been a model citizen and incredibally peaceful, but they are basslets and will defend their territory if need be.

 

[captainandy]

Wouldn't buy. I see my yellow, at most, once a month.

 

[Sigmund]

I have had a Gold assessor basslet in my 150 for about a year.

Great color, interesting, especially since he swims upside down as much as right side up, and eats everything. No aggression at all with anything in the tank, very passive.

I would suggest that you have a tank with lots of overhangs, this way it will feel protected, but you will still be able to see it. Mine spends most of it's time under one of my three overhangs upside down.

 

[Wolverine]

They're usually peaceful, except to similarly shaped fish. That especially includes other assessors. In general, yellows are a little more aggressive than blues, so if you put one of each in a tank, my money is on the yellow.

As mentioned, they can be pretty cryptic. We had one in our 200g, and we didn't see it for about 3 months at a time.

 

[Wolverine]

We had one in our 200g, and we didn't see it for about 3 months at a time.

The one we had in that tank was blue.

 

[nivram]

Once an individual becomes established, which may take many months, he will defend his territory against certain fish. In my tank my yellow assessor has chased a small ecsenius blenny and a firefish. The chase was very brief, no harm done, and settled down after the blenny and firefish had been there for a week. Other than those occurances my assessor has been a model citizen and incredibally peaceful, but they are basslets and will defend their territory if need be.

I have noticed similar behavior. For the most part a very peaceful fish.

 

[alprazo]

I have an ORA yellow pair. I thought they had died. Then about 2 years later I saw them swimming one night. I now occasionally see them before the lights come on.

 

[rollermonkey]

Awesome! Thanks!

My plan now is to load my 29g-cube like such:
1st: Blue Assessor
2nd: two neon gobies
3rd: two Ocellaris Clownfish

(with appropriate quarantine time between)

And Sigmund, I'm hoping that I can aquascape the LR when I get it into an arc shape from front left corner bowing towards the back, then towards the right rear corner. I hope to incorporate three arches into the shape.

 

[Sigmund]

Rollermonkey,

Regarding the aquascaping good to hear, chances are this will increase your chance of seeing it more.

Also as mentioned in this post, I have also noticed that at Sunrise and Sunset especially that mine will come out and swin in the quarter of the tank that is getting hit with ambient light. I assume this is some instinctual behavior as my Possum Wrasse and Pink Streaked Wrasse like to do it as well. Also when the assessor does this he usually is swimming on his side orienting the sun to his top, as the ambient light comes in from the side. Pretty funny to see.

 

[Sigmund]

Rollermonkey,

Regarding the aquascaping good to hear, chances are this will increase your chance of seeing it more.

Also as mentioned in this post, I have also noticed that at Sunrise and Sunset especially that mine will come out and swin in the quarter of the tank that is getting hit with ambient light. I assume this is some instinctual behavior as my Possum Wrasse and Pink Streaked Wrasse like to do it as well. Also when the assessor does this he usually is swimming on his side orienting the sun to his top, as the ambient light comes in from the side. Pretty funny to see.

 

[Hoosierfan]

I've been thinking about getting a yellow assessor too. However, I kind of enjoy seeing my fish, so based on the info provided here, I'll probably go in a different direction.