Emperor angel vs. Koran angel and other fish questions

[GoinSalt]

How do you tell Emperor and Koran angel juvs apart when they have very similar colors?

Also, could a flame angel (dwarf) get along with a reg. angel?

Do different gobies get along? I have a (I believe) a watchman goby but he doesn't sift the sand. What kind of sand-sifting goby can I use?

Thanks for the help
Nate

[Ninong]

Juvenile Pomacanthus imperator angelfishes are bluish black with concentric white circles: http://www.fishbase.org/Photos/Thumb...ry.cfm?ID=6504

Typical juvenile: http://www.fishbase.org/thumbnails/jpg/tn_Poimp_j5.jpg

Juvenile Pomacanthus semicirculatus angelfishes are bluish black with concentric white semi-circles, which is why they are called "semicirculatus." http://www.fishbase.org/Photos/Thumb...ry.cfm?ID=5663

Typical juvenile: http://www.fishbase.org/thumbnails/jpg/tn_Posem_j3.jpg

The difference in the pattern is very obvious once you compare one with the other.

In general, angelfish are more likely to be aggressive with their conspecifics and congeners and possibly even fish that only look them themselves and more accepting of fish that are different from themselves.

Many gobies are aggressive with other gobies but I'll let someone else field that question for you.

[RayPollett]

Without knowing which goby you have it would be hard to say for sure. Some will fight and some do not. On sandsifting gobies, a lot of them slowly starve to dead in tanks over the course of months. They need plenty of life in the sandbed or regular addtions of pods to the tank to survive.

[GoinSalt]

Without knowing which goby you have it would be hard to say for sure. Some will fight and some do not. On sandsifting gobies, a lot of them slowly starve to dead in tanks over the course of months. They need plenty of life in the sandbed or regular addtions of pods to the tank to survive.

If I remember correctly, the guy at the lfs said it was a watchman goby. I'm not 100% sure. I have never seen him sift any sand. He usually just picks up the food that floats down to his level. Every time I feed the tank I see him eating, so at this point, he's definitely not starving.

But I was at the lfs last night and the guy tried to talk me into a sandsifting goby (can't remember the name of it -- It looked black and white, almost like a FW pictus catfish). Anyway, he said that this particular fish sifts the sand looking for stray food that I feed, that it doesn't look for life in the sand. I'm guessing he was wrong?

Nate

[Ninong]

There are several different species that are commonly called "Watchman Goby." Usually they just stick a different adjective in front, such as "Yellow Watchman Goby," "Pink Spotted Watchman Goby," etc. All of them eat tiny microcrustaceans found on the sand bed, either on the surface or just beneath the surface. Some will form symbiotic relationships with pistop shrimp. All are territorial and not likely to accept an intruder of the same or similar species unless they are a mated pair or unless you have a very large tank.

What Ray is trying to tell you is that they require high quality live food in order to thrive. This is the same situation you run into with Mandarin Dragonets. They need lots and lots of copepods and other microcrustaceans in their diet. Frozen foods would be a good substitute but not as good as the live stuff provided by lots of live rock and/or a good refugium. Even if certain fish are eating, they may not be getting the proper nutrition from the food they are eating if it isn't exactly the same as what they have evolved over thousands of years to process. Some fish can die of malnutrition even if you see them eating all the time. Sometimes their digestive systems are highly specialized and they just don't do as well when they do not get the stuff they are used to getting in the wild.

Gobies are bottom dwellers (without swim bladders) that specialize in eating tiny organisms they find in and on the sand bed.

[Ninong]

Anyway, he said that this particular fish sifts the sand looking for stray food that I feed, that it doesn't look for life in the sand. I'm guessing he was wrong?

Nate

How could I possibly have missed that one.

Yeah, I'm guessing the same as you. Next time you see him, ask him what the same fish would be doing to survive in the ocean if you are not there to provide the "stray food" for it to search for.

[RayPollett]

There are several different species that are commonly called "Watchman Goby." Usually they just stick a different adjective in front, such as "Yellow Watchman Goby," "Pink Spotted Watchman Goby," etc. All of them eat tiny microcrustaceans found on the sand bed, either on the surface or just beneath the surface. Some will form symbiotic relationships with pistop shrimp. All are territorial and not likely to accept an intruder of the same or similar species unless they are a mated pair or unless you have a very large tank.

What Ray is trying to tell you is that they require high quality live food in order to thrive. This is the same situation you run into with Mandarin Dragonets. They need lots and lots of copepods and other microcrustaceans in their diet. Frozen foods would be a good substitute but not as good as the live stuff provided by lots of live rock and/or a good refugium. Even if certain fish are eating, they may not be getting the proper nutrition from the food they are eating if it isn't exactly the same as what they have evolved over thousands of years to process. Some fish can die of malnutrition even if you see them eating all the time. Sometimes their digestive systems are highly specialized and they just don't do as well when they do not get the stuff they are used to getting in the wild.

Gobies are bottom dwellers (without swim bladders) that specialize in eating tiny organisms they find in and on the sand bed.

Ninong, Very well said.

ray