Fin Question....

[SuckerLove86]

Ok, this may seem like a dumb question, but just out of curiousity, should fish be alternating fins when they swim or flapping simultaneously?

 

[Yenko]

It depends on what fins you're talking about, but it probably varies from fish to fish.

 

[Dwarfs]

Yeah, It depends on the fish Puffers use their pectoral fins to propel themselves and their tail to steer, while other fish use their tail for propulsion, and their pectorals for stabilizing/steering

 

[SuckerLove86]

It's just one of my little black mollies. She was taking a quick salt bath and I guess I observe wierd things. She was alternating her pec fins and I didn't know if that was normal or if my molly is just..... special.

 

[Dwarfs]

A lot of fish do that when they are sitting still/ kind of stressed

 

[Angry_Platy]

Don't they change which fins move depending on whether they want to go forward, turn etc.?

 

[sylvia]

When moving forward (most) fish will use their tail. The pecs are used to steer and stop. When hovering, they will move the pecs rapidly while not doing much with their tail. The alternating of the pectorals is usualy seen when they are steering, stabilising or when trying to swim backwards. Rapid movement of the pectorals whilst staying still is often an indication of stress (coupled with fast, heavy breathing). This is based in particular on one of my swordtails so I would expect similar behaviour from a molly. Most fish use their fins this way.