Legos as tank decoration

[Charles 8]

My family is really into legos and there was a discussion on if having a lego centerpiece decoration would harm the fish in our aquarium. Does anyone know? We generally keep cherry shrimp, guppies, and otocinclus.

Thanks in advance!

Charles

[Fish Folk]

On 8/11/2021 at 11:20 AM, Charles 8 said:

My family is really into legos and there was a discussion on if having a lego centerpiece decoration would harm the fish in our aquarium. Does anyone know? We generally keep cherry shrimp, guppies, and otocinclus.

Thanks in advance!

Charles

I think it's no problem. The only issue would be if there was some leeching of dye into the tank. I've seen it done before in the old "home show" videos that Cory used to share. Go for it! I think a massive, crashed, partially buried Imperial Cruiser in a 55 gal on the face of a sandy planet-substrate would be epic!

[lefty o]

i think lego plastic is pretty inert. i would wash them very well in hot water before using. only downside i can think of, is im not sure how well the cavities of trapped air will fair. even with some commercial decorations, trapped pockets of air can become stale, and breed some nasty stuff.

[Griznatch]

As far as I know Legos are inert. Unless you have some that have been exposed to heavy detergents or some other household chemical they should be ok. I think I saw a post in here - yeah here it is

Interested to see what you come up with !

[ArchwayAquatics]

Lego plastic is freshwater tank safe. I'm not sure how much concern trapped air going stale would be if the tank has decent circulation or an air stone - but would it make it too buoyant? I've wondered if it needed to be assembled under water to avoid floating?

[B1gJ4k3]

I've done it before with some success. I think as long as you stick to the hard plastic bricks, you should be fine. It's when you get into some of the other, more bendy pieces where I would question whether or not things would start to leech.

The problem you'll have is getting it to sink/float consistently. I had a floating Lego submarine in my betta tank (linked above) that floated for months and looked great. It then started to grow a bunch of green spot algae on it since it was so close to the light, so I put my nerite snail on it and just his weight caused it to sink to the bottom and never float again. So, if you're planning on trying to have it float, it could be tricky, but if you're wanting something on the bottom of the tank, you'll probably need to anchor it somehow.

[Guppysnail]

On 8/11/2021 at 11:24 AM, lefty o said:

trapped pockets of air can become stale, and breed some nasty stuff.

I just had this happen with a made for aquarium deco…nasty and quickly.  The legos themselves should be safe they are made for kids of real young ages that stick them in their mouths. Maybe use aquarium silicone to fill them in as you build ?

[Gestaltgal]

On 8/11/2021 at 11:24 AM, lefty o said:

i think lego plastic is pretty inert. i would wash them very well in hot water before using. only downside i can think of, is im not sure how well the cavities of trapped air will fair. even with some commercial decorations, trapped pockets of air can become stale, and breed some nasty stuff.

Would building the project in the tank help with that?

We could turn each brick upside down before adding it to the piece as a whole, being sure the whole project is then saturated. Would it stress out fish too much?

This assumes a small project of course.

[CT_]

Red and Yellow /had/ cadmium in them.  As long as they're not "vintage" (Post mid 80's i think) they're okay, until we discover something else horrible in them.

[Guppysnail]

On 8/11/2021 at 1:30 PM, Gestaltgal said:

Would building the project in the tank help with that?

We could turn each brick upside down before adding it to the piece as a whole, being sure the whole project is then saturated. Would it stress out fish too much?

This assumes a small project of course.

It becomes stagnant water that’s what happened in mine maybe drill circulation holes in each piece?

Edited August 11, 2021 by Guppysnail

[Matt_]

On 8/11/2021 at 1:30 PM, Gestaltgal said:

Would building the project in the tank help with that?

We could turn each brick upside down before adding it to the piece as a whole, being sure the whole project is then saturated. Would it stress out fish too much?

This assumes a small project of course.

I recommend trying this with a couple of basic Lego bricks first to understand the time involved before going all in on an underwater build.  You are going to have to use a pipette or a syringe to remove the air from every hole in every brick since it is really hard to get all of the air out of each brick.  It still might be really cool to see something like the LEGO City Ocean Exploration Ship - 60266 floating in a tank though.  This actually gives me an idea for the old 38 gal tank that is sitting in the basement.

[Charles 8]

Thanks everyone for the ideas!!!

[BlueLineAquaticsSC]

It’s all fun and games until a guppy steps on a LEGO in the middle of the night

[lefty o]

On 8/11/2021 at 7:27 PM, BlueLineAquaticsSC said:

It’s all fun and games until a guppy steps on a LEGO in the middle of the night

if you have never heard a fish scream!🤣