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Are all darters snail-eaters?


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#1 Guest_leviathan0_*

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Posted 27 February 2009 - 03:42 PM

Probably a dumb question, but I thought I'd ask.

Do all darters eat snails, or is it just certain species like Rainbow?

#2 Guest_ashtonmj_*

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Posted 27 February 2009 - 03:52 PM

No. In fact, only a few darters (mostly those in the subgenus Imostoma) feed primarily on snails in the wild. Very few darters consume snails at all. If I can find my copy I'll post it but see Haag and Warren 2006. They post most of their pubs via the Foresty Service website.

#3 Guest_keepnatives_*

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Posted 27 February 2009 - 08:11 PM

No. In fact, only a few darters (mostly those in the subgenus Imostoma) feed primarily on snails in the wild. Very few darters consume snails at all. If I can find my copy I'll post it but see Haag and Warren 2006. They post most of their pubs via the Foresty Service website.

When you say very few darters consume snails at all are you still referring to "in the wild". In my aquariums most darters I've kept ate snails with great relish and needed no time to learn they were a food source. Rainbows, greensides, spotted, tessellated, banded, bluebreast, fantails, orangethroats, redfin, redline all come to mind.

#4 Guest_rjmtx_*

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Posted 27 February 2009 - 09:41 PM

I know the darters our lab has done life histories on in the Edwards Plateau don't eat snails. An interesting one that comes to mind is the River Darter (Percina shumardi) that eats snail in other parts of its range, but apparently not in the disjunct population in the Guadalupe.

#5 Guest_leviathan0_*

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Posted 28 February 2009 - 04:42 AM

Well, I am more concerned with whether or not they would eat snails in captivity, regardless of what they do in the wild.

The reason I asked is because I am thinking about starting an invertebrate tank, and wanted to add just a few fish. I was looking at darters (specifically Least, Brown and Swamp Darters) but I do hear about Rainbows and such eating snails, so I wanted to ask if it was typical of all darters or just a few species. Of course, this tank may never come to fruition, but I thought it was worth asking.

#6 Guest_ashtonmj_*

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Posted 28 February 2009 - 09:05 AM

Yes I'm still saying that most other darters in the wild do not eat snails. Why would they when there is an abundance of macroinvertebrates? In an aquarium you have none of that natural food so of course they will oppurtunisitcally feed on any snail put in front of their face. Seasonal feeding on snails by river darters

That's actually quite interesting about the Guadaplupe population of river darter. Are there no snails or are they not abundant?

#7 Guest_Clayton_*

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Posted 28 February 2009 - 02:16 PM

Darters only eat very small snails, so you can still easily keep a population of snails in a darter tank. You probably just won't see the population grow much. I'd be curious what other kinds of inverts you are planning to keep in the tank.

#8 Guest_rjmtx_*

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Posted 28 February 2009 - 02:45 PM

I wouldn't say darters only eat small snails as evidenced by the linked paper above "The largest snail found in guts (10.4 mm in length) was eaten by a 66.6-mm SL fish that had also eaten 13 other snails averaging 6.3 mm in length." (Haag and Warren 2006). They might generally eat small snails in the wild, but in a tank...

There are plenty of snails in the Guadalupe, native and invasive. Off the top of my head, the preferred food is Ephemeroptera.

Also, if you're starting an invert tank with a few fish, I'd be much more worried about bugs getting munched down than the snails.

#9 Guest_ashtonmj_*

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Posted 28 February 2009 - 04:16 PM

Well there might be a difference between plenty of snails and plenty of snails in the same habitat as river darters. Maybe the same types of snails, mostly Pleurocerids, aren't available?

I would think the darters you indicated would be okay with snails. I have a tank with three swamp darters and plenty of native snails from the rivers are in the tank. Their mouths are very small and just not a food item they seem to prefer or have the mouth parts to handle.

#10 Guest_rjmtx_*

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Posted 28 February 2009 - 06:53 PM

There are plenty of pleurocerids in the Guadalupe. It is the southernmost River Darter, so it might have something to do with prolonged breeding seasons of inverts since the snail eating seemed to be seasonal (I just skimmed the paper, though). Maybe River Darters just prefer Tex-Mex to escargot.

#11 Guest_keepnatives_*

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Posted 28 February 2009 - 07:17 PM

Darters only eat very small snails, so you can still easily keep a population of snails in a darter tank. You probably just won't see the population grow much. I'd be curious what other kinds of inverts you are planning to keep in the tank.

That may be somewhat true for the darters that actually swallow the snail shell and all. But the ones I have actually eat just the snail out of the shell so shell size isn't as big a limitation. I also have swamp darters and have never seen them eat snails.

#12 Guest_keepnatives_*

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Posted 28 February 2009 - 07:47 PM

Yes I'm still saying that most other darters in the wild do not eat snails. Why would they when there is an abundance of macroinvertebrates?

Maybe they just taste better :smile2: Or easier to catch. Maybe there are seasons when they are more abundant. What amazed me was how anxious they seemed to be when snails were provided even though I regularly provide live waterbugs, scuds and blackwoms. Greensides, Rainbows and Variegates went wild over them. I've never studied small fish gut contents so my question may be kinda stupid but I've been stupid before so...how distinguishable would a snail's body be in a fishes gut if they didn't eat them shell and all?

#13 Guest_fundulus_*

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Posted 28 February 2009 - 08:37 PM

...how distinguishable would a snail's body be in a fishes gut if they didn't eat them shell and all?

It depends on the fish. A lot of cyprinids (like Notropis) have surprisingly efficient pharyngeal jaws that can mash up and shred food items; a snail's foot might make it through relatively intact but then be acted upon quickly by digestive juices. I'm less familiar with what might happen with darters, although I'd guess that they have pretty efficient pharyngeal jaws too. Carnivores typically have fast-acting digestive systems.

#14 Guest_leviathan0_*

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Posted 28 February 2009 - 10:51 PM

Thanks for the input everybody.

I'd be curious what other kinds of inverts you are planning to keep in the tank.

Also, if you're starting an invert tank with a few fish, I'd be much more worried about bugs getting munched down than the snails.


I was looking mainly at snails and ghost shrimp, perhaps clams depending on how I'll set it up. I've crossed out crayfish, and I don't know much (if anything, really) about aquatic insects, so I haven't considered them yet. I'm not entirely sure which snails I'll be adding - I can't collect any myself, and the wanted ad I put up some time ago hasn't generated any responses yet.

As for the darters, the reason I looked into those three specifically is because of their smaller size, which I was hoping would mean they wouldn't be able to eat any snails.

#15 Guest_darterpro_*

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Posted 01 March 2009 - 02:34 PM

As well as they eat snails, tubifex bloodworms, etc., I feed mine goldfish food. It really brightens up their color! I am somewhat good with darters, mine have adapted to eat goldfish food in about a week.

#16 Guest_JohnO_*

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Posted 02 March 2009 - 11:58 AM

Mine love the brown shelled snails I find in my own creek. They don't usually last more than a day. The darters seem to swat the snail with their tail to roll it over, then one quick jerk and it's out of the shell and down the throat.

I did find some headwater darters in a creek that was packed with black shelled snails. Inadvertenly dropped a few of those black snails into my tank, and the darters won't touch them. They must taste bad.

#17 Guest_ashtonmj_*

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Posted 02 March 2009 - 12:29 PM

I'd just like to reinterate that everyones observations so far have been of snail consumption in captivity. Yes, when darters with large enough mouths are presented snails they will eat them in aquaria, but they'll also eat flake food and that certainly doesn't exist in the wild.

#18 Guest_Skipjack_*

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Posted 02 March 2009 - 11:33 PM

I have kept alot of darters in captivity. I have witnessed very little snail consumption, with one exception. The Greenside darter ( E. Blennioides)seems to me to actually be a snail feeding specialist. They actually grab the snail and suck it directly out of the shell. In fact I have never had any kind of snail population in a tank with greenside darters. I frequently have harvested snails from other tanks to feed them to Greensides. In fact I have a snail problem right now, and kept several Greensides this weekend just to get the population in check. I cannot verify this behavior in the wild, but I would be surprised if snails did not make up a large part of their diet.

#19 Guest_jblaylock_*

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Posted 03 March 2009 - 08:10 AM

I did find some headwater darters in a creek that was packed with black shelled snails. Inadvertenly dropped a few of those black snails into my tank, and the darters won't touch them. They must taste bad.


I still have a few of those snails from that area, my darters won't touch them either.

#20 Guest_JohnO_*

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Posted 03 March 2009 - 11:42 AM

What I have observed over the years from my own creek:

It has a healthy population of rainbow and fantail darters. Also has some brown shell snails, fairly fat shell maybe 3/4" in length. I find the snails mostly in very shallow water, too shallow for the larger darters to live. I don't find snails much in water over 1-2" deep. In the tank, I've seen fantails devouring snails, and it's a deliberate action. Swim up next to it, eyeball it, swat it with the tail or pectoral fin to roll it over, and suck the snail out of it's shell. I'm no trained scientist, but this looks to be a practiced act, like they've done it before. And the fact that I can't find the snails anywhere but in shallow water might indicate that something is eating the ones that venture into deeper waters.

So I can't speak for darters every where, but from what I've observed, the fantails of Griers Creek appear to be expert snail hunters. Except for those black snails that came out of Crooked Creek. Nobody in the tank will touch them.




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