Safety of collected wood

[Loracidlover]

I recently purchased a 800 litre seabray tank (72x30wide x24) at a knock-down price, and am in the process of collecting wood to decorate it. I plan on fixing many branches/roots to the back and side of the tank above the water line. I intend to screw small pieces of slate to the branches using A4/316 marine grade stainless steel screws, and then attach the slate to the tank wall using silicone. The bottoms of the branches will reach down through the substrate and be attached to the tank base in the same manner

I've been collecting dead (but not rotten) beech branches, which are surprisingly difficult to find, then vigorously cleaning them with a wire brush attached to a power drill, then baking them at ~60C for 12+ hours (in the warming oven of an aga).

Is this likely to render the wood totally "safe"? I'm particularly concerned about some pieces I have found which, though not rotten, have black/reddish fungal discolouration of the wood under the bark, and smell slightly "mushroomy". Once the wood is scraped/brushed, the fungal coat is removed, as shown below.


Would this piece be fully safe once cleaned/baked? Or does the presence of fungal spores present a danger?

Also, is marine grade stainless steel safe for use in aquariums over extended periods?

Finally, here's 2 pictures of a beech cave I constructed, I feel I must show it off due to the inordinate amount of time it took to make.



Cheers, Conrad.

[MatsP]

As long as you know that the wood in itself is known to be non-toxic, it should be fine.

Wood known to be toxic to fish is pretty rare. Avoid anything that doesn't have leaves (pine, spruce, yew, cedar and such), ash is rumoured to be toxic, but not certain.

Fine to use is any fruit-trees from the garden (apple, pear, cherry, and so on), as is all native decideous trees (beech, birch, oak, alder, willow, and so on).

If you have Panaque or Ancistrus in the tank, you can put "green" (freshly cut) branches in the tank with no worry. If not, then soak it for a long time until it sinks.

I don't feel it's needed to "clean" the wood excessively, or trying to disinfect it in any ways. There are very few pathogens that transfer from wood to fish. The exception is if you collect the wood in freshwater lakes/rivers - even then I think the risk is relatively low, but there is a slight possibility.

Fungused wood will definitely suit panaque and ancistrus, and I doubt that it's harmful to other fish.


--
Mats

[LeeRoy]

I like to collect wood for some of my tanks also.
That hollow log will make a nice addition to any tank.

I have noticed that some woods will leach tanic acid into the water.
This can be harmful to your fish. It will discolor the water to.

I have a small fish pond in the yard, I will clean a piece of wood, then submerge it in the pond for a couple months to help leach off some of this acid. This will also tell you if it is safe to put in you tank.

Be sure to wash said piece of wood well before putting it in the tank.

LeeRoy

[MatsP]

I have noticed that some woods will leach tanic acid into the water.
This can be harmful to your fish. It will discolor the water to.

First time I've heard anyone say that tanic acid is harmful to fish - it is essentially tannic acid that is making blackwater "black". Sure, if the pH drops very much, then it's not good for the fish, particularly if the drop is sudden. Sudden drop in pH would indicate that the KH (buffering capacity) of the water is too low - which is a problem whether there is wood or not in the tank.

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Mats

[Birger]

Wood known to be toxic to fish is pretty rare. Avoid anything that doesn't have leaves (pine, spruce, yew, cedar and such), ash is rumoured to be toxic, but not certain.

Pine,spruce,fir is pretty well all I use as they are the main trees around here, I do not use anything fresh though...I get driftwood or pieces that are submerged out of the rivers and reservoirs.

I just clean off the dirt and in it goes without too much prep work.

Birger

[Viktor Jarikov]

I've been told before that I must pressure wash the loose parts off of driftwood. Do you find this excessive? Would just a reasonably thorough manual cleaning be enough to avoid a messy tank with floating debris, pieces of bark, rotten parts fallen apart, etc.?

Also, Birger, are you not worried about harmful parasites and/or bacteria being in the wood you put in your tank?

Say for my outside pond, whenever I stock aquatic plants in it, like hornwort I collect in local swamps in the spring, I presoak it in a weak solution of potassium permanganate (strong antiseptic) for 1-2 hours. Would you say this is unnecessary? My koi sellers tell me this is a must.

[MatsP]

I've been told before that I must pressure wash the loose parts off of driftwood. Do you find this excessive? Would just a reasonably thorough manual cleaning be enough to avoid a messy tank with floating debris, pieces of bark, rotten parts fallen apart, etc.?

This really depends on the level of "muck" on the wood, and the type of fish living in the tank. Vegetarian/wood-eating plecos definitely clean the wood very well, so there isn't much point in cleaning it other than mud and general dirt...

Also, Birger, are you not worried about harmful parasites and/or bacteria being in the wood you put in your tank?

Say for my outside pond, whenever I stock aquatic plants in it, like hornwort I collect in local swamps in the spring, I presoak it in a weak solution of potassium permanganate (strong antiseptic) for 1-2 hours. Would you say this is unnecessary? My koi sellers tell me this is a must.

To some extent, I think this is worse when it's an outside pond, because the temperature range will be the same. But yes, if it's wood from freshwater rivers, I would clean it and disinfect it (perhaps boil it).

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Mats

[wrasse]

That is a superb beech wood cave you have made. You've gone to a lot of trouble to make the pieces good for aquaria.
You might find they get a bit fungused when in the tank, but it won't harm the fish.

[Loracidlover]

Thanks for the replies guys, sounds like I may be being a little overzealous with the baking scrubbing etc. from what you say Mats. Still, I figured since these pieces are all going to be siliconed in to the tank, I had better make sure they won't be a problem

That is a superb beech wood cave you have made

Thankyou It took forever, bashing away at a log for about three hours with a large flat-bit. I plan to make a few more, I'd really like to make one big enough for my large L24 (he's around 12" long) but that may be too much of a challenge!

You might find they get a bit fungused when in the tank

I hope the soaking I am doing to remove tannins (after having been wire brushed and baked) should limit the growth of fungus/slime once in the tank.

Here's my collection so far

[MatsP]

I actually like the "weak tea" colour that tannins give the water. But maybe I'm not usual in this...;)

--
Mats

[kizno1]

The tunnels look great. Ive always gave the bits of wood ive collected a good scrub and boiling it might not be needed but better to be safe than sorry IMO. I prefer the brown colour the tannins gives the tank I think it looks better and more natural. Ive been collecting a load of wood the last few weeks for my 150G and have them all soaking in a storage tub. some fungus did appear after a few days but after a week or so it disappeared.

[apistomaster]

About holding wood down until it is water logged.
I use a few 1/4" diameter wood dowels cut very slightly longer than the tank interior is wide. These dowels are then wedged in cross-wise at as few strategic locations as necessary to hold the wood down. I normally collect wood as water logged as I can and clean them up and install them asap so I have a head start with the water logging process. I used a couple long branches about 5 to 6 inches in diameter and almost 5 and 4 feet long in a 6 feet long 125 US gal tank. I was able to hold them down with only 2 inconspicuous dowels and was able to remove the dowels in less than 6 months. These large and long pieces were placed so they cross each other from opposite ends and that made it possible to only use 2 dowels.
Every piece of wood and aquarium 'scape is unique so different methods have to be used but I avoid making any methods so permanent that I can't change it easily in the future.

[Birger]

Also, Birger, are you not worried about harmful parasites and/or bacteria being in the wood you put in your tank?

I am spoiled in the fact that I do not have to worry about this, not that our water is lifeless but if you put your hand or walk in the rivers around here you go numb right away...it is that cold, even in the summer, life is limited and specialized in these cold temps, so no I am not worried about it...but it is a good point to note that not every place is like that and there are nasties that can lurk depending on the source.

It is interesting to see what types of crawlies and things came out of the wood, when collecting recently in Virginia I found some of the many (quite large and strange looking) larvae in the water just as interesting as the fish.

Birger

[Bas Pels]

@ parasites

Only speaking in general terms - what lives above water will not survive below - and vice versa

Therefore - anything you find what is dry will be good to put into your tank (unless it's toxic, obviously)

Using this rule of thumb, I did provide my fishes a few times an unexpected lunch

[LeeRoy]

It is my understanding that tanic acid will also lower the oxygen levels in the water.

In days gone by, people would use nut, leaves and bark from some trees. They placed large amounts of this in a pool in a slow flowing stream. It would cause the fish to be stuned and come to the surface, making capture easier. This was learned from folk-lore so take it as given.

LeeRoy

[MatsP]

There are certain plants that either stop fish from breathing, or make fish stunned/dead from toxins. Rotenone is a "stuns fish quickly" toxin, produced from the root of a tropical plant, used by scientists to collect all [or nearly all] fish in a small portion of water.

But the reason that blac-water is black is tannic acid, which is also why it's pH around 4. If tannic acid was directly toxic to fish, there would be no (oxygen loving) fish living in such rivers. And I think you'll agree that there are. Sure, fish that are not liking soft, acidic water, will not like lots of tannic acid.

Also, wood breaking down in the water will consume oxygen to some extent... But it's not the tannic acid that causes that, to the most part.

--
Mats

[LeeRoy]

MatsP

Thanks for clearing this up for me. I see that it wouldn't be the tanic acid that does the work.

Thank You

LeeRoy

[grokefish]

I usually bung mine in my pond for a couple of months (no fishes in that pond)
It has the advantage of adding something to eat to the wood aswell.

[apistomaster]

Tannins and lignans are some of the phytochemicals which may be released from woods, especially wood which has cured for some time in an anoxic environment.
Lignan is such a weak acid that to make aquarium water more acidic would hardly be noticeable unless the water is pure as in RO water. Most tap water has sufficient buffering capacity that the wood will not have much effect on the pH.
Both tannic acids and lignans are each a group of chemicals found in so-called black water, typically very soft and acidic water. While wood contributes a fraction of the sources of chemicals that give black water it's name and chemistry. The primary cause of black water is the percolation and longer retention periods of rain water through very thick and extremely large areas(often thousands of square kilometers) of decaying leaf litter, peat and not so much of wood as a percentage of the composting surface layer.
There is an association of these chemicals in aquarists' minds with black water.

This contrasts considerably with the use of relatively small amounts of "seasoned" wood kept in an aquarium and it's effect on the pH of aquarium water. That wood may release enough lignans and tannins to influence the color of the water but the relationship between the color of water induced by wood in not directly proportional to the ability of the wood to influence the pH.
We know that peat has the ability to lower the pH and even function as an ion exchange media but it is very dependent of the source/type/quantity of peat and the water must have little to no KH to produce much change. In this respect, it is much more influential than wood per unit of mass. To put it another way, it is well know that it can take a prohibitively large amount of peat filtration to soften and acidify tap water of even only moderate hardness. The surface area available of the peat particles is many orders of magnitude greater than surface area of some pieces of wood in a fish tank.

I decided to write this as food for thought because in this and other tropical fish fora I keep reading posts by aquarists which seem to imply attributes of the influence wood in aquaria has on pH and hardness than it deserves.
There are other properties that decaying dead plant matter can impart to aquarium water in a positive way for breeders of black water fishes due probably to the fundamental molecular structure of these phytochemicals to estrogen precursors but wood is not nearly as useful in this regards as peat and/or large amounts of leaf litter. The type of plants that compose this peat and/or leaf litter matters a great deal. The ubiquitous Tropical Almond Tree, Terminalia catappa, is one of the better known sources of the tannins and lignins now in wide use in the hobby as a material to make already very soft water chemistry more similar to naturally occurring black waters but we tend to use the leaves of this plant not it's wood.

[MatsP]

Larry,

I agree that:
1. People on forums talk about "wood makes water acidic", and like with peat, unless the water is already soft, it will have little or no effect - assuming the amount of peat or wood is non-silly amounts. Dumping 25kg peat in a 50 gallon tank will have an effect - it will also fill almost the whole tank with peat, which is probably not such a great idea.

2. Blackwater is indeed formed in a giant tea-brewing process of detritus, mainly leaves and other vegetable matter.

--
Mats

[Viktor Jarikov]

Larry, Mats thanks a bunch!

In days gone by, people would use nut, leaves and bark from some trees. They placed large amounts of this in a pool in a slow flowing stream. It would cause the fish to be stuned and come to the surface, making capture easier. This was learned from folk-lore so take it as given.

Interesting. I should give it a go next time I play in the local waters... sounds like an excellent way to kill an afternoon just need to research what to put in the water.

[MatsP]

I think almost all known natural fishkillers are tropical plants (not to be confused with East Fishkill in Viktors neck of the woods - give or take a few hundred miles).

http://en.wikipedia.org/wiki/Rotenone

--
Mats

[Viktor Jarikov]

Thanks Mats for the nice link - I had no idea about rotenone. Why not clove oil? Too expensive or not available?

East Fishkill? What are you talking about? I think you are just kidding with a straight face. Or bragging your geography knowledge

http://en.wikipedia.org/wiki/East_Fishkill,_New_York
As the New York metropolitan area continues to expand along with the high price of housing, East Fishkill has become an exurb of New York City.
One early settler arrived around 1759. The town of East Fishkill was established in 1849 from the eastern part of the town of Fishkill. The name "Fishkill" comes from that of the river which the Dutch settlers in the area called "Vis Kill" which means "Stream full of fish".

[MatsP]

I think the use of Rotenone in killing fish is that it's stronger, more potent. Remember, this is used to kill all fish in a small lake or section of river, and clove oil is needed in volumes of 50 drops per gallon.

Yes, I was bragging about my random knowledge of geography. ;)

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Mats

[LeeRoy]

I would like to add a word of caution, the fish and game dept. of all the states might not take this use of capture to be legal. This would not be a usefull way of collecting fish, they would be DEAD.

LeeRoy

[MatsP]

Scientists only keep dead fish.

--
Mats

[Viktor Jarikov]

I would like to add a word of caution, the fish and game dept. of all the states might not take this use of capture to be legal.

Of course, thanks LeeRoy. I was thinking more in terms of an experiment - what makes fish sedated out of what's at hand in nature in any particular spot. Still, park rangers may not necessarily believe my high and well justified semi-scientific motives...

This would not be a useful way of collecting fish, they would be DEAD.

that's the other part of the experiment - what/how much kills and what chills (sedates)...

Scientists only keep dead fish.

Physical organic chemists?


(kidding... you likely mean all scientists...)


(kidding again)

[MatsP]

Just in case it's not clear, I meant scientists that work on describing existing/new species of fish, and collecting fishes for museums, etc. Museums don't keep fish in tanks (public aquariums do). Some times scientists will capture live fish and release them after measuring/weighing/counting/photographing/etc, in which case it's obviously NOT a good idea to use something that kills them...

But most fish that is used for describing new species comes out of the water into either formalin or a freezer [possibly via formalin/alcohol/rotenone]

--
Mats

[apistomaster]

In Washington State we have some fine Trout lakes managed for "quality Fishing" and the Spiny Ray crowd is always illegally introducing sunfish and Bass so cyclically these Trout lakes are treated with rotenone. Many of our best Trout lakes must be treated almost every 10 to 15 years. These are lakes of 100 to 500 acres so rotenone is potent and they allow the dying fish to be collected by anyone who cares to because rotenone is not harmful to people. Some of the targeted fish always manage to survive so this goes on endlessly over the years. A lot of money is spent every year clearing quality lakes of trash fish like carp, catfish and unwanted spiny ray fish. It is never used in our rivers because it is so difficult to achieved a lethal concentration throughout the streams and would wipe out entire class years of Salmonids. It also wipes out most of the aquatic insect larvae so it takes a few years for treated lakes to fully recover after being treated. In streams, introduced species are less of a problem to the Pacific Salmon species and sea run rainbow trout(Steelhead) but a predatory native species does take a heavy toll on the smolts working their way back down stream to the Pacific while passing through the many impoundments behind hydroelectric dams. These are the Northern Pikeminnow or Squawfish.
Image of Northern pikeminnow http://californiaoutdoors.files.wordpre ... =500&h=185
These frequently reach 75 to 100 cm and each one can consume thousands of smolts. The State has placed a bounty on them of US4.00 each and the amount goes up the more you catch. Many people fish for them and make a lot of money but they must use conventional fishing tackle; netting is not allowed. http://en.wikipedia.org/wiki/Ptychocheilus_oregonensis
They were not a problem until the dams were constructed and native runs nearly exterminated but they eagerly await the release of the smolts produced and released by the Salmon and Steelhead hatcheries.

Maybe because I have become a bit jaded over the years but when I want to kill a lot of fish I hit them hard on the head or throw smaller specimens very hard on concrete. I never have used any chemicals to kill them but if I chose to do so I would probably use a cup of household bleach and just start the tank over again

[andywoolloo]

I actually like the "weak tea" colour that tannins give the water. But maybe I'm not usual in this...

I'm right there with you Mats. Love it.