Spiny Dorsal Fin

[JEAE21]

Some of my fish have them folded down and flap them up on occasion.
Does this mean that they are un-healthy? Or is it because of the water current?

But after I turn off the lights at night, most of them put them up(which I'm thinking is because they are more vulnerable to predators at night)

 

[guppy]

It depends on the species, many fish only fully flare the dorsals as threat or mating displays.

 

[JEAE21]

this one(big goldfish) has it down and is at the bottom of the tank.
while the others are really active swimming about and having their spines up most of the time.

 

[sandtiger]

Is the goldfish in question holding all of it's fins close to it's body or just the dorsal?

 

[JEAE21]

all of them. he does though, put them up when the lights go off.
he seems better than yesterday though! a little more swimming..just the fins.

he doesn't seem to be getting food too..

 

[Mystix212]

Almost all of my fish have fully erect fins at night. Its not a predatation device or anything. Just, like we humans sometimes sleep fully strechted out? *Shrugs*. Most of my fish are soft rayed anyway.

 

[JEAE21]

*but they're not sleeping...

i'm just worried that he's sick or something..

 

[Mystix212]

He is NOT sick. Recent studies do show that fish need lights out time.

 

[sandtiger]

Actaully, I don't want to jump to conclusions but he could be sick. If he is the only fish laying on the bottom, not eating and holding his fins close to his body then it could be an indication of something.

Clamped fins. Typically an indication of poor water quality or a symptom to another illness.

This fish with ich also has it's funs clamped.

 

[niblit]

My first step is always to test the water.Then go from there.