After years with a 5 gal, last week I bought an established 35 gal (was told it was 40!) tank that's 1 year old. Came with a 5" Tiger Oscar and 3 Giant Danios. Water levels tested and still good, kept same filters for now (two Top Fin 40s) so it's full of the "good" bacteria. I have found a home for the current inhabitants since I want to fill it with small schools of neon tetra, regular-sized danios, etc.

First question: it came with a bubbler - two skinny flexible tubes that are under the substrate, spitting up little bubbles. Is there a purpose other than to attach a treasure chest to? I mean, it looks kinda cool I guess.

My next question is about the ugly substrate. My dream for this tank is to be a community tank that will eventually look like a natural stream bed - driftwood, rocks, natural colored pebbles, etc. Currently it's full of black, neon green and red pebbles and a couple of plastic plants. I didn't want to remove them yet since they were part of the original tank with all the goodies growing on them. When/how/should I get rid of the fake-looking pebbles?

Thanks in advance!

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- New-to-me 35 gal tank, slowly being updated & stocked
- 5 gallon hex tank, currently inhabited by my 12 yr old's "free fish" from science class - a feeder goldfish that's loving his new home, thriving and doubling in size in the last 6 months!

What a good find! And it sounds like you've got some fantastic plans. If the tank has an under gravel filter that might be why the bubblers are there. The air would cause a suction to clean out all the goop that falls through the filter into the empty space created by the grate, which creates an "under gravel filter".

If there isn't an under gravel filter, then my guess is the same as yours that they probably used it to power a bubbling piece of decoration.

As far as the gravel, since you've got the cultures from the filter AND a great substrate culture you could probably just save a cup of the current substrate (try to avoid saving all the neon stuff) and remove the rest as soon as you want. Once you get the new substrate (of your choice) you can just mix in the cup of established gravel, or even just put the cup in a corner that it will be less noticeable.

Hope that helps!

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IslandRzrbk

35g Planted Freshwater tank - 4 platies, 2 veiled angelfish (juvenile), 1 pictus catfish (juvenile), 1 golden Chinese algae eater (juvenile), 1 candy-striped plecostomas (juvenile), 1 female veiltail betta

That oscar is going to outgrow that tank fast as they get to be 12"+. so unless you are going to buy i bigger tank, you might want to consider giving it away. For the bubbles it add needed air into the tank.

You can change the substrate no problem! Just wait until the filter is finished cycling. Once the filter is done cycling, let the tank 'be' for a few weeks (just to be sure everything is stable) and then change your substrate. Some people do it, half at a time, but many people have since stated that it can be done all at once, so long as your filter is well established. :D

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20g Heavily Planted http://www.aquariumforum.com/gallery...00&ppuser=8981
36g Bow Front Heavily Planted http://www.aquariumforum.com/gallery...00&ppuser=8981