Stocking a 20 gallon with GloFish.

[NV Pack]

I'm new to aquarium life, but I've read enough to be somewhat informed. I'm interested in stocking a 20 gallon tank with Glofish danios and tetras. Given 1 inch of adult fish per gallon, with danios growing to approx 2 inches and tertras to maybe 3.....Can I safely stock a 20 gallon tank with 6 danios and 6 tetras and also throw in a "sucker fish" "pleco". I also want to have a fiddler crab roaming the bottom feeding on debris. The 6 and 6 on the Glofish is prob maxing out (or, is that already too many?), but is there still room for the sucker and fiddler crab to help keep the tank clean? My initial thoughts are it's ok to add the 2 cleaners because they stay out of the way of the general swimming area of the tank. Yes, no?

Thanks!



So, I just read the below item about plecos and aquarium setup. Minimum 55 gallon tank for one of these? Can that possibly be the correct minimum?


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http://animal-world.com/encyclo/fresh/catfish/Plecostomus.php

Aquarium Setup

A minimum 55 gallon aquarium is recommended for the Pleco. Although when small they can be kept in a smaller aquarium for a short period of time, these are fast growing fish and will soon need to be moved. Some driftwood or other decor should be provided to give them caves to hide in during the daylight hours. They also like a well planted tank, but use hardy species as they can damage delicate plants as they move around grazing on algae growths. They are also jumpers, so be sure to have a cover on the aquarium.

Keeping some wood in the tank offers a number of benefits besides offering a place of refuge. Their rasping action to remove algae from the wood provides a perfect place for more algae to grow maintaining a constant food source for this fish. Also, the cellulose in wood is necessary for their digestive process.

• Minimum Tank Size: 55 gal (208 L) - Juveniles may be kept in a smaller aquarium for a short period of time, but these fish are fast growing and will need a larger tank as adult.
• Suitable for Nano Tank: Sometimes
• Substrate Type: Any
• Lighting Needs: Moderate - normal lighting
• Temperature: 66.0 to 79.0° F (18.9 to 26.1° C)
• Range ph: 6.5-8.0
• Hardness Range: 1 - 25 dGH
• Brackish: Sometimes - In the wild they live both fresh and brackish water, as some are ound in the mouths of rivers flowing into the ocean. But in captivity they do fine in a freshwater aquarium.
• Water Movement: Moderate
• Water Region: Bottom - The Pleco or Plecostomus will swim in the bottom of the aquarium.

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[tanker]

12 glowfish would be fine in a 20gal. Plecos will grow too big, it will grow slowly, but will out-grow the 20gal.
Also fiddler crabs are not fully aquatic and will need a place to come out. They also have been known to climb out of tanks and die.

 

[Cryolath]

As far as stocking goes I don't have that much experience with schooling fish, a good website that gives a decent baseline advice for stocking (not always entirely accurate, but often good as a place to start) is aqadvisor.com.
Glofish are zebra danios: danio rerio,
Glotetras are (I think) White Skirt Tetras: gymnocorymbus ternetzi

Stocking using the inch per gallon rule isn't really effective, waste output and behavioral requirements (very active species vs. more sedentary species) etc. should all be taken into account as well.

Definitely a no on the Fiddler crab, they are slightly more terrestrial than aquatic and require a land area, they also need brackish water.

Plecos are mostly confusing because there are many different species and many stores aren't very specific. The information that you found is most likely for the 'common' pleco which can often be any one of a number of species, most of these will reach up to 1-2 feet in length, which would definitely not fit into a 55gallon tank either.
There are several smaller species of pleco, the bristlenose pleco is one, which I believe stays at about 4" full grown, which should be fine in a 20 gallon tank. The problem I have with them is that they produce an incredible amount of crap for their size, and I would rather clean up slightly more algae than have to siphon out that much more poo. They should also have driftwood in the tank that they can munch on as well as being fed a variety of blanched veggies.

I'm a little bit uncertain when you say 'cleaners' what exactly you are expecting them to do. Each animal added should be fed according to its needs, and will then produce waste as a consequence, which actually makes the tank dirtier, a higher bioload requires more frequent/larger waterchanges etc. If you are expecting them to eat leftover food then the simple answer is that there shouldn't be any leftover food, and you are feeding to much. Or you are feeding in a way that the fish can't get everything (flakes get sucked into the filter, etc.) in which case you need to change how you're feeding so that they can get to all of it before any of it goes to waste. I ended up switching to pellets because it seemed like there was always some bits of flake food floating off into the tank.

Sorry about the essay, let me know if I've made any glaring errors and good luck with your new tank!

 

[Tifftastic]

Given 1 inch of adult fish per gallon, with danios growing to approx 2 inches and tertras to maybe 3

When you say "tetras" do you mean the "Glotetras" or are you thinking of just tetras in general? Tetras are a huge group, so it would help if you could be specific as to what species you are thinking about.

As far the one inch per gallon rule, its garbage. The rule doesn't take into account body mass, a 1 inch danio will have much less mass than a 1 inch cory cat for example. Things like waste production and swimming needs have nothing to do with body length and more to do with species, diet and body mass.

also throw in a "sucker fish" "pleco"

As far as plecos go, saying "pleco" doesn't really help either. There are MANY species of algae eating catfish that fall under the pleco label. In my personal experience and opinion you could house a single bristlenose pleco, clown pleco, or rubber lip pleco as they all stay under 4 inches. However, the clown requires driftwood in its diet as well as fresh veggies/pleco specific food. In fact all of the species of plecos should be fed either fresh/frozen blanched veggies or a sinking food designed for them. They cannot thrive on algae alone. If you only want a pleco for the purpose of eating algae, you're better off just scrubbing the tank.

I also want to have a fiddler crab roaming the bottom feeding on debris.

Crabs: nope. Simply don't do it. The fiddler crab that you mentioned are more terrestrial and have special diet requirements. The red claw crabs that PetSmart sells, also require space to get out of the water, will eat small fish (like the danios), and prefer brackish water. Not to mention all the species of crabs are known to climb airlines/filter intakes and escape the tank. For "cleaning up debris" on the bottom you're better off feeding lightly and gravel vacuuming regularly. The crabs will only eat left over food anyhow and will make more of a mess than anything, and again should still be target fed a species appropriate diet.

So, I just read the below item about plecos and aquarium setup. Minimum 55 gallon tank for one of these? Can that possibly be the correct minimum?

For the common pleco species that article is referring to a 55 gallon tank is actually FAR too small. These species can reach 1-2 feet or more and require massive tanks in order to keep them healthy.