Pond Boss Forums POND CONSTRUCTION Creating habitat Why fish cribs work and why they fail

This article by Eric is the most comprehensive list and overview of fish cribs and habitat

preferences utilized by most of the North American fish species I have ever come across.

His career spanning over 30 years in underwater fish photography has given him and now us,

a look beneath the waves to understand what he and his colleagues have been seeing for years.

In over four years of extensive study, I have not found anyone else who understands

fish behavior and has the photos to prove his findings like Eric. Groundbreaking

information never before available, will help us understand how to best construct,

place and revitalize new and existing fish cribs and why. Did you know fish preferred

to be able to swim under the crib, not to mention key points like density, height

and proximity to aquatic vegetation?



Eric and I talk regularly about habitat, cribs and fishy stories surrounding this

underwater world which he is so familiar with. He has installed some of our

artificial habitat units in his own lake for long term monitoring as well as other

lakes in the area to see just how well they stack up. Although skeptical at first,

he has seen the aquatic growth, fry and predator fish utilizing our products and

find we meet most, if not all of his criteria for why our products work so well.



Sit back and read into the underwater world of Eric and his team as they share

their insight of how, why and where fish cribs work from the first hand account

of divers under the surface.



Take a look through his site and the thousands of images he has compiled

over his career under the water's surface. This is only the start of fully

understanding and improving the fish cribs we install. The Fishiding pictures

he has taken and observed will only help us improve on how best to help our

fisheries. Throughout this diving season, Eric and his team will continue to dive

and document our cribs and others for all to enjoy and learn from. Preferred

crib color, fish abundance, water fertility/clarity and sunlight penetration are just

a few of the many unanswered questions we are beginning to understand with

Eric's help. Watch for a new, taller model to come out soon!

Why fish cribs work and why they fail

This was an excellent article from your friend peepaw. I was intriged by the fact that white pvc was unnatural looking and fish were scared to silouette against it. I wonder how recycled green pvc would fare?

I thought the same thing and talked to Eric for a couple of hours today. here's a reply he gave me a few days ago when I questioned the white material as well. Although we do make some of our cribs with white siding material, it's only about 15% of what we take in. More brown and grey colors seem to be most prevalent in our neck of the woods.
(Eric's response:)

First off, I do my photography in very clear water, so all my observations are from high clarity lakes mainly in Wisconsin and Michigan. All my conclusions are based on these waters.
I can’t say if birch bark or white PVC would have the same effects in the Mississippi River or Toledo Bend reservoir or any other turbid water, because I’ve never gone under the surface in dark water to see if fish behavior is different in those kinds of conditions. I would venture to guess that in dark or turbid water, where color and ambient light is lost quickly, it’s not as significant a factor. That’s my guess-but it’s not based on any observations I’ve personally made.

Here’s what I’ve seen regarding birch trees in clear water lakes. When the white bark is still attached to the tree, small fish tend to avoid it. The reason i think is easy to understand. The dark body of the fish is silhouetted against the birch and easy to see by predators. (other fish, and ospreys & kingfishers from the air) Dark bark, surfaces or backgrounds tend to hide the fish. They blend right in and are camouflaged. This is why fish have dark backs and white bellies. Seen from above, they blend into the lake bottom. Seen from below, they blend into the bright sky/surface.

Eventually the white birch bark wears away and the exposed tree parts are darker and the trees become more of a magnet for fish.

Light sand bottoms where fish would also stand out are also not favored by fish. Darker, mucky or leaf covered bottoms will have more fish for exactly the same reasons.

When you think about a lake system, there’s really nothing that naturally occurs in a lake that’s white. It’s really an alien color to a lake. Sure, there might be very bright, light-colored sand beaches, but these areas if they’re lacking any plants, rocks, or woody debris are typically not areas where fish hang out. Fish by and large are always trying to hide. Hide from predators, and hide from prey. They don’t want to be noticed, so anytime they’re silhouetted against light backgrounds it makes them very visible and vulnerable. If you’re a predator fish, all the potential prey will clearly see you. If you’re a forage fish, you’ll also be highly noticeable. So being seen so easily has no benefits of any kind. I think this is why fish avoid light backgrounds.

Regarding the fishiding structures:

I don’t think the samples I put in Lake Anna tells us much actually.
It’s true that largemouth bass and rock bass have built spawning nests next to the bases and I’ve seen newly hatched fry around them. But they seem to group under a piece of PVC that offers shade from the sun. They seem to position themselves under a panel, if there’s no panel directly underneath it where they are silhouetted.
I’ve also seen Age 1 and 2 bluegills around the fishiding structures in good numbers. This would seem to contradict my previous statements. But these bluegills tend to be almost white.
If you’ve ever fished in really clear water maybe you’re noticed that the fish lack deep coloration. Bluegills especially seem to take on a very light, almost white colored appearance in very clear lakes. The bluegills in Lake Anna have always been very light colored fish lacking any bars or red and olive colorations you typically associate with bluegills. A fish with this color, or lack of pigment would actually blend right in to the white PVC quite well. A darker surface would tend to make these fish stand out, so in this case they seem to be a good match for each other.

It’s important to remember that a key difference between fishiding and the white PVC piping that’s shown in that picture I included, is that the PVC piping doesn’t seem to collect much organic growth. It’s about as white as it was the day it was dropped in the lake. I don’t see green algae clinging to it like it does on your product. I don’t know why more organic material isn’t forming on it the way it does with your fish hiding panels. Perhaps the surface is coated with something, or the curvature has something to do with it. I’m not sure. Maybe you have some ideas. (PVC pipe has an algae prohibitor because it is normally used in sewer/water pipes, thus the reason folks have learned to sand it before sinking.)

You know David, I’ve given a lot of thought to your fishiding structures over the last couple of years. I guess I’m really stuck. I don’t feel like I can whole heartedly endorse them, but at the same time, I can’t dismiss or condemn them either. You seem to be onto something and there does seem to be genuine applications for them. I also don’t feel like my observations of them on a single infertile lake in Wisconsin can be used to gauge their performance or lack of it in other other lakes with different conditions. In 3 weeks, I’ll personally be inspecting the fishidings that Roger placed at two separate locations in Round Lake (Sawyer County, WI). Perhaps observing them and seeing what’s going on with them on a different lake will give us more information that will allow us to make some better conclusions.

Thank you Peepaw.

That's a nice article. Candid and real life experience.

Great photography at his website too!!!!!!!!!

Nice work. I will copy to structure archive.

Personal experience here. I think not much organic growth is forming on the plastic is because the lake is infertile. I've put white PVC pipe in a vert fertile pond (visibility 12"-18" max.) and after a week the PVC was already coated. I did NOT sand it at all, as it was plumbing for a waterfall feature.

Mine got covered up too. I wonder if it also has to do with the pipe manufacturer. Possibly some skip the algaecide in the mixture to cut back on expenses?

I dunno. This was 3" dia. PVC.

So many folks talk about sanding the pipe?
We certainly don't have any of those issues with our stuff fortunately.
Eric notes that he can only speak of where he dives but we all know how many variables come into play.

The important part is we are using these long lasting leftovers to feed and protect our fish.

Recently added some bucket structures in my pond. Blue Lowe's buckets with black poly drip tubing. Interesting read from Peepaw about colors.

Have any of you worked with paint on materials in a pond? If it would improve the effectiveness and would be safe and long-lasting, it may be worth it.

Thanks for the link, some real good information in there.

Yellow plastic gas line seems too work great.. Lots of growth and fish within weeks..

The verdict is still out on color. We have installed dark Blue, Green, Red and Brown along with the lighter colors to see which, if any the fish prefer. Watch for updated photos and a story from Eric with news of our findings. If installed in more fertile waters, growth fully covers the color of material hidden inside and seems to have no effect on fish behavior/preferences.

One other proof that is coming out of our studies are the fry, shad and baitfish color/preferences. Hide the bait and the predators will be nearby to feed. Small bluegill and shiner were stacked in the cribs only a hour after sinking and blended well with the lighter colors, choosing them over the darker colors along side of them.

My guess is we will find color has little importance compared to location and other available habitat. Water quality is the other most important part of the puzzle, changing color and shape of any material submerged, the more fertile the waterway.

Mine were covered with growth in a month very fertile water.. Kinda sucks

Once the artificial habitat is covered with periphyton color will not be very apparent nor important.

Wow, I read the article and now see why my previous pallets were unsuccessful. I now know what is needed but have to figure out how to drag the pallet/brush structure out into the lake without a big pontoon boat available. Any suggestions? Thanks!

Float them out. Tie something onto it so it'll float, but you can cut the floats off and let it sink. For instance an upside down 5 gallon bucket will give you around 40# of lift (filled with air of course).

Any further comments on the PVC coatings? Will my green PVC sewer pipe need to be sanded or just put it in as is?

Put it in as is.. it may take a little longer but everything coats that I've seen sit in water long enough..