ok #1: unlike "blueberry" and "strawberry" tetra, Glofish are not dyed, they are indeed bred in those insnae colors, they are genetically engeneered for it...personally we call them frankenfish and i feel they charge way too much for them, but unlike injected dyes these fish dont suffer and the color doesnt wash out after a couple months. NEVER buy dyed fish, dying fish is cruel and makes for weak fish...glofish however are freeky zebra danios and if you get them from a good source, actually hardy fish (zebras will survive a cycling tank!)
that being said:
general rule of thumb for TROPICAL fish is 1 gallon of water per inch of fish AT ADULT SIZE! so if your fish is going to grow to 3 inches, he needs 3 gallons at least, preferably from day 1...
this rule does not work for very large or long or very active fish, a 10 inch gouramie is NOT going to be happy in a 10 gallon tank, for those guys i like to do LENGHT (or height for angles) of at least tripple the fishes full grown lenght (so a 10 inch gouramie would need at least a 30 inch long tank, thats a 40 gallon breeder tank right there!)
it is OK to LIGHTLY overstock a tank if you are willing to do weekly waterchanges and have EXCELENT filtration (ie my cichlid tank is overstocked by about 1 fish (it helps curb agression) but i also run double filtration and do weekly water changes and cleaning!
eclips are good little tanks and the filtration is good enough that some mild overstocking is not going to do too muhc harm with the right fish...but your still going to be limited in 6 gallons.
a 10 gallon is a good size for a SMALL community tank, and a 29gallon is actually one of the best sizes to start out in (the bigger the tank the more "diluted" problems will be meaning it will take a larger fluctuation to mess up your tank than it would in a tiny tank...(hope that makes sense)
kissing goramie are not suitable for a 6 gallon, kissers can grow on average 8-10 inches.
gouramie in general do not mix well togehter in smaller tanks, a pair of dwarf gouramie need at least 10 gallons each...gourmai are labyrinth fish and related to Betta, they tend to be very teritorial (they will often fight with betta fish too!)
the "kissing" kissing gourami do is their way of fighting, males (and females) will lock lips in battle!people think aww its so cute there kidding, when in reality its all out war...!
the red tailed shark, also comonly red finned and rainbow, are not suited to most aquariums, they will easily break 4-6 inches and while fairly docile as youngsters once maturity kicks in you will find he will become the tank terror, i suggest nothing smaller than 29 gallons for a single redtailed and even that is pushing your luck. they are also not algea consumers like often adversited they are scavengers...
the Corydora, which comes in many cute color combinations of stipes spolids and spots in black white and green is a much better scavenger for any tank, but MUST be kept in groups of 5 or more! there incredibly social! these guys do an excelent job of cleaning up the dropped food but they WONT usually eat most of the algeas found int he aquarium
for "sucker fish" your refering to algea consuming "sucker mouth fish" the fish that would fall into this catergory are usually avid algea eaters (or at least start out that way)
most people imediatly think of the pleco...do NOT and i will repeat do NOT get a common pleco, they will BUST TANKS at 12+ inches full grown! they are all too often bought as babies for tiny tanks and die early for it.
there are smaller species like the bristlenose that grow in the 4-6" range, but these guys are usually much harder to find. Pleco of any kind ONLY consume alge when young, as they mature they prefer a diet of srimp flakes.
another popular one is the chinese algea eater. this is another one that is often sold to unknowing first time fish keepers, the CAE is generally a terrible fish for beginners, they are known to be hyperactive, agressive as adults and will even latch onto many fish! they too can grow LARGE (these guys are better suited for a semi agressive tank)
some better coices.
the Siamese algea eater, it will grow to about the same size as its chinese cousin but their agressivness is much lower
MY favorite especially for small tanks though is the OTTO, these small indescript colony loving algea eaters will eat the widest array of alge types (they will eat the stuff other alge eaters wont!) and they work CONSTANTLY, if your ottos not on the move or chowing on alge theres something wrong wiht him lol. these guys also have a much lower waste output than other fish, because of this they make a good addition to an already fuller tank in need of a clean up crew, but get 3 or more if you want them to be realy happy and healthy!
my FIIRST suggestion to you would be look into getting a larger tank, a 10 gallon full tropical set up all glass brand wil cost you about the same as a fancy 6 gallon eclips, ive seen the 10 gallon all lass, with light filter heater water conditioner, net, sample food all for about $60! and the foot print of a 10 gallon tan is not much bigger than the 6 in terms of its actuall foot print!
a 20 gallon long or 29 gallon will cost you a little more but open your options up amazingly!
the bigger the tank the more options!
ill give you some thoughts on what i would do...using the fish you like or alterinitive that would work, ill only list COMMON fsh that you could find at most petstores as im sure your not going to want to go searching and spending a fortune on ardr to find species your first time around
remember LIGHTLY overstocking your tank is OK as long as its LIGHT and your willing to do the waterchanges to keep the tank healthy...
for the 6 gallon
1 DWARF grouami (they come in some stunning colors have the personality of the bigger gourami but grow 2inches, they would do best in 10 gals but can be ok in 6) (2")
5 glo-fish (1.5-2" each)
3 otto cats (1" waste output per fish)
yes this tank would be overstocked, most zebras will grow 1-1.5" but some can reach 3" so you will have to keep an eye on them...but with upkeep this tank could work well.
put in some wide leafed plants like amazon sword and some caves to create some territory for the goruami.
for a 10 gallon the set up id stay with the same but it would be a much nicer sized tank for them
for 20 gallon
1 dwarf (2") or 1 blue spot (6") or 1 opaline (4")
5 glo-fish (2") or Cherry barb (one of the most peacfull of the barb 2") or Glowlight tetra (2") or black neon tetra (2") or pristella tetra (2")
3 otto
5 corydora
for a 29 gal:
as above but pick 2 groups of the 5's
good luck and have fun fish keeping is an awesome hobby but addictive.
we had lots of fish when i was a kid...but it wasnt untill i entered my mid teens i realy got into the hobby for myself (and i think that was more that i had to wait till i had my own money)
from there it grew, i started with a single better, next came another betta and a 10 gallon, then came another betta and a 29 gallon, then another 10 gallon, then a second 29 gallon and another betta and most reacently a 55 gallon.
right now i have set up
55 gal peacock
29 gal community with 1 blue gourami, a retailed rescue, and some black neon tetra
3 5 gallon betta tanks
plans to reset up
2nd 29 gallon, not sure what as yet...mabe a couple goldfish...
10 gallon shell dweller tank or dwarf puffer tank
7 gallon not sure yet...
edit to add: cuase you want guppies...
i wouldnt add guppies if you want grouami unless your doing the 20-29 gallon tank...they share too much of the same space and their bright colars can end up in agression.
with guppies you certainly CAN do all males (and its suggested because guppies breed like bunnies!) if you mix males and females its 1 male to 2-3females and expect LOTS of babies!
if your planing on doing guppies they count as 2" per fish and id skip the glofish/danios and cherry barbs, danios are notoriously fast and tend to be fin nippers who will disturb your guppies.
however, seeing you like the guppies...
heres some other suggestions
6 gallon
3-6 male guppies (lots of plants to give each boy his own territory) add some ottos or corydora and it would be a very pretty tank.
10 gallon
same as above, or add an extra filter (20 gallon filter on a 10 gallon tank or 2 10gal filters) and add some glowlight, or blackneon tetra (regular neon tetra are stunning but overbreeding has made them extreemly delicate fish, black neons ar emuch hardier!)
20 gallon
same as 20 gal above but with guppies instead of gourami and no barbs or glofish/danios
29 gallone, same suggestions as above, exchange gourami for a group of guppy and no glo-fish or barbs.