Can there be too much flow for a fish?

Jvesche20 · Jan 17, 2019

Recently I built a sps frag tank. I have a 700 gph pump and a 900gph Power head in a 25 gal tank. The tank goes about 3 1/2 - 4 feet up and about 10 ft from the sump. I have my dt and frag tank linked together. I added a small tang about 1 inch in side that I’m not sure of the species and percula clown fish. The tang doesn’t seem to mind the flow he goes around picking at the small rock pile that I have in the frag tank for the fish to hide. While the clownfish seems to be swimming in one corner all day. I have 3 other clowns and he seems like he’s having to swim much harder to keep up with the flow. Can having this much flow kill the clown or is he fine?

Hitman · Jan 17, 2019

I don't think it will hurt them but some fish just don't like strong flow and others are just not strong swimmers and are slow like lion fish.

davocean · Jan 17, 2019

Flow should not be an issue, but a tang of any kind and how many clowns do you have in a 25g?
That could be an issue

Jvesche20 · Jan 18, 2019

davocean said:
Flow should not be an issue, but a tang of any kind and how many clowns do you have in a 25g?
That could be an issue

Just the one clown fish. I have an assorted tang at the fish store they only got 3 inch when they matured. The fish was in a 20 gal tank at the fish store so didn’t think there’s an issue with putting the tang in there as a juvenile. The tang turns black when matures. All I have in there is coral frags, 1 hermit and the 2 fish but I’m just scared this fish is a weak swimmer and can’t handle the flow

KrisReef · Jan 18, 2019

When I first set up my 75 reef flat I had lots of flow, and yes you can swim a fish to death.

Jvesche20 · Jan 18, 2019

KrisReef said:
When I first set up my 75 reef flat I had lots of flow, and yes you can swim a fish to death.

I’m going to move it to my DT right now I’m scared he’s gonna die

Hemmdog · Jan 18, 2019

Absolutely you can swim a fish to death

Jvesche20 · Jan 18, 2019

Hemmdog said:
Absolutely you can swim a fish to death

Good to know didn’t know that. I thought maybe the clown would go hide under the rock but it never moved from the corner looking like it was swimming so hard all day for about 3 days

blackizzz · Jan 18, 2019

Based on the numbers you've provided, and that we're talking about a clown (notorious for weird behaviour, amongst others only hanging in corners / swimming erratically in the spot) I'd say you're fine.
You're probably at 50-60x turnover, which unless it's an extremely narrow flow pattern shouldn't be a problem for all but a few fish.

Just my two cents

Waters · Jan 18, 2019

As stated, it entirely depends on the fish. A batfish or lionfish cannot handle the stronger flow.....other fish such as tangs thrive on reefs where the water is breaking constantly against the rock.

DSC reef · Jan 18, 2019

The tang in the small tank will like the flow but hope you have a plan on rehoming, especially if you dont know the species as they grow fast. I'd keep an eye on the clownfish. If it cant keep up it most likely will stay hidden and have problems feeding as well.

tupes · Jan 18, 2019

Jvesche20 said:
Just the one clown fish. I have an assorted tang at the fish store they only got 3 inch when they matured. The fish was in a 20 gal tank at the fish store so didn’t think there’s an issue with putting the tang in there as a juvenile.

1. Can you post a photo of this tang? Personally I haven't heard of an "assorted tang". I've especially never heard of a tang that only get to a max of 3" when mature. Most juvenile tangs that I've see are 2-3".

2. Just because a LFS has a fish in a smaller tank doesn't mean it will be ok in that size tanks long term. LFS use smaller tanks just to have a bunch of tanks and usually the fish dont stick around long enough in the store to really let the fish suffer swimming room.

Hope this helps some.