Dense material safe for aquariums?

[twofalafels777]

I want to sink a tiny glass air-filled, sealed bottle with trinkets into my nano fish aquarium. The items I want to put in the tiny bottle are not waterproof (bones, gems) or I would simply fill the bottle with water to sink it. What material can I add to the tiny bottle to help it sink? Fish-safe material preferred in case it breaks or leaches into the aquarium, but not necessary as I don't picture that happening.

 

[.Scott]

I would try two things:
1) seal the items in a plastic bag to keep them dry. You can suck most of the air from the bag to reduce buoyancy.
2) tie the whole thing down with some kind of weight. An easy way do this is with a plastic bag or plastic wrap that should be pretty invisible when surrounded by water.

 

[Klystron]

Do you have aquarium-safe stones? You could place the tiny bottle under a stone or among a cairn.

 

[twofalafels777]

I'm basically trying to reverse nature -- I want dry land plants growing in a concealed glass container underwater. But I need something else extra-dense to add to it to help it sink! What are some extra dense materials that I can find easily?

 

[Tom.G]

Aquarium gravel, glass.

Avoid plastics unless they are stated as being aquarium safe, most plastics will leach out chemicals over time.
Avoid metals, except perhaps Gold or Platinum (others?), many will poison the water with metal ions.

Cheers,
Tom

p.s. If you can, please post photos of your results.

 

[russ_watters]

How about super-gluing it to the bottom?

 

[Tom.G]

Super-glue is often, or related to, cyanoacrylate. That is a skin irritant, causes serious eye damage, and is a suspected carcinogen.

Somehow, that seems incompatible with fish.

 

[BillTre]

Superglue available to most people won't hold up too well long term in the water.
Cynaoacrylics intended for surgical use might work.
Hot glue from hot glue guns (looks like polyethylene) works fairly well in aquaria, but does not stick to a lot of things.
Polyurethan glues are water proof and resistant to long exposures, and stick real well. As manifested in the expanding foam insulation sealants they get used a lot on aquaria. Gorilla glue is a less foamy version. If it expands, it will probably be lighter than water.
Silicon aquarium sealer (as opposed to non-aquarium silicon sealer, which has things like anti-fugals in them that are bad for fish, biological filters, or both) will glue certain substances well, especially glass.

Aquarium gravel, glass.

I second these choices. Along with very non-water-reactive rocks.

 

[russ_watters]

Super-glue is often, or related to, cyanoacrylate. That is a skin irritant, causes serious eye damage, and is a suspected carcinogen.

Somehow, that seems incompatible with fish.

Superglue is used to close wounds, and I'm seeing no indication of it being a carcinogen.

The fish will not be breathing the fumes as it dries.

 

[Bystander]

Avoid metals,

..., of course, until recently, aquarium plants were marketed with twist-ties of lead foil to hold the bundles together, and weight them down.
YMMV

 

[DaveC426913]

I'm not sure how buoyant your trinket-trove will be, but many weighty materials won't be sufficient to keep it secured, except in bulk.

I'd tie it to a large flat rock with fishing line.
You could also glue it to the bottom (or the rock) with aquarium-grade silicon seal.

 

[Ibix]

I'm basically trying to reverse nature -- I want dry land plants growing in a concealed glass container underwater.

Aren't plants net producers of oxygen? So wouldn't plants in a sealed container suffocate themselves for the opposite reason that we'd suffocate in the same environment?

 

[DaveC426913]

wouldn't plants in a sealed container suffocate themselves

He said "concealed" not "sealed".

It might be a challenge to provide land plants with the essentials to live on a continuing basis, but I don't rule it out.

 

[BillTre]

You could get emergent plants which grow out of the water from being planted in the water.
Or there are a lot of plants that can grow completely out of the water, but are sold to be grown in the water (where they also survive).

 

[DaveC426913]

Ah you beat me to it.