Stocking rule of thumb? and other questions

[slappycd]

Hi all,

This is my first post and first tank and I'm a little confused on the stocking rule of thumb.....here are my stats and history.

20g Hex 20" tall by 16" diameter. Surface area 210sq in.
Aquaclear HOB filter
6" areator stone
Cycled for a 5 weeks. Water changes every 3-5 days.

week 1 fishless cycle for three days. Came home from LFS with Bio Spira for a quick bacteria colony and fish.

Male Neon Swordtail
Male Lyretail Baloon belly molly
Male Dwarf Blue gourmi
Female (I think) Albino Cory Cat

Well the gourmi died two days later and then the rest came down with ick, at such time I begain treating with salt.... Icks gone and so is the Lyretail molly. The gourmi never ate and seemed to be "gasping". Lack of O2 so I got the areator. Lyretailed died during salt treatment....LFS told me all these fish were consider hardy. Too much faith in the Bio Spira and the Fish store I guess. All this time water test were within safe limits....

Amonia 0
Nitrites 0
Nitates 0+
ph 7.5+
gh 150 - 200 using 50% distilled (thoughts on peat?)

At 4 weeks (5 days ago) I got 3 more Albino Corys and a female Yellow Swordtail. One cory died the next day, otherwise the rest are going good.

current totals

2 swordtails
3 cory cats

2 hornwart plants

wanna school more corys (2) and another female swordtail.... the yellow is being endlessly "courted" by the male and maybe a school of Neon Tetras (6). My concern is will this be overstocked?

3 swordtails * 2.5" = 7.5"
6 cory cats * 1.25 = 6.25"
6 neon tetras * 1" = 6"

19.75 total fish inch..... Does that sound right?

I've search for a rule of thumb and it looks like there are to schools of thought. fish Inch per gallon (20) or fish Inch per sq in of surface area divided by 12 (17.5).

Thoughts? Please check my logic.

----Other questions----
Will my Hornwarts eliminate the need for the areator?
How can you tell there is an O2 shortage?
Thoughts on peat moss as a water softner?

Thanks

Slap

[liv2padl]

the are no rules of thumb that are worth your effort to understand. the number and size of the fish you keep in your tank should be based on several factors. it should not be based solely on the chemistry of your water nor on the magic of the inch per gallon myth. it's more than simply a matter of successfully keeping the ammonia and nitrites at zero or the fact that you may have "great filtration". certainly these are important issues, but one of the most important factors is almost always overlooked. the number and size of fish that one maintains in a tank should be predicated on the "biology" and behaviour of those fish.

this means that the interraction of a mixed community tank and/or the behaviour of a single species is the single most important factor to consider. you want the fish you're keeping to have the ability to exhibit "normal" and functional behaviour. normal behaviour is important. abnormal behaviour results in stress. stress leads to disease. disease can lead to death. for example:

1. if species (A) does not get along with species (B), then these fish don't belong in the same tank no matter how few fish you have or how large the tank. "getting along" is based on the visual and behavioural Q's that each fish species is genetically programmed with. this is why African cichlids don't belong in the same tank with Central American cichlids for example. Africans don't "understand" Central American fish speak and this leads to behavioural problems and stress.

2. if species (A) has specific food or water chemistry requirements which are completely different from species (B), then these fish don't belong in the same tank no matter how large it is.

3. if species (A) is aggressive and defends a territory of 2 square feet, then you cannot expect to successfully keep more than one of these fish in a tank which is smaller than 2 square feet. convict cichlids are an excellent example of this ... this little fish aggressively defends territories of about two square feet give or take. if you have a tank which allows only that much room and no more, the convict will defend the entire tank to the detriment of any other fish (no matter how large it is) in that tank.

fish need room to swim without having the rest of the tanks inhabitants "in their face" continuously. when crowded, fish exhibit stress syndromes that result in poor color, improper fin form, insufficient metabolic development, do not exhibit proper musculature, do not develop properly functioning organ systems and most importantly slowly lose their inherant resistance to disease. this results in a significantly shortened lifespan and along the way, lots of diseases for which the poorly conditioned fish is a good target..

think about your local lake or river --- the fish are free to inhabit whatever space suits them biologically. if it gets crowded by their standards, some will disperse and move to other areas where they again have the space they need to exhibit functional behaviour.

it's difficult to allow for that "space" in your tank -- the fish have no escape within the confines of your tank so it's up to you to insure that the fish have that space in the first place. if your tank "looks bare" .. it's probably just right.

[FreddytheFish]

Well, liv2padl pretty much covered it, all I can add is:

The only stocking rule of thumb is to use common sense and do research.

[you made me ink]

cant get it much better than that research is key and no impusle fish buys or you might find yourself :shark:

[Web Gazelle]

Male Neon Swordtail
Male Lyretail Baloon belly molly
Male Dwarf Blue gourmi
Female (I think) Albino Cory Cat

....LFS told me all these fish were consider hardy...

No, Corys and Dwarf Gouramis will not tolerate toxin levels of a cycling tank.

[slappycd]

Thanks all,

Unfortunatly the "waters are still cloudy". :confused:

padl, you leave alot to interpretation. for example assuming the inch-surface area is the base line, it seems stocking all the same fish raises the baseline and less compatible lowers the baseline. The key as I see it is establishing the baseline. These fish are chosen for there communal personalities.

I guess I'm looking for suggestions on what direction one might take knowing my situation.... I know I need at least 1-2 corys and possibly another swordtail (f) by the way I think my new sword is pregnant. :eek:
I was hoping for one more colorful species.

Thanks again

Slap

[FreddytheFish]

I was hoping for one more colorful species.

How about a dwarf gourami? Beautiful fish, and since they don't school, they don't fill up your tank that much, and they make a great centerpiece fish.

[liv2padl]

padl, you leave alot to interpretation yes, i suppose so. i couldn't possibly cover all biotypes and every personal situation. the examples i gave were just that ... examples. one has to do alot of research before buying fish in order to understand their ability to live in a community situation.

in my opinion, you're already stocked to maximum density. in any tank, the surface area is the most important parameter to consider .. not the stated gallon capacity. since a hex has less surface area than a standard tank dimension, your twenty gallon tank can actually hold fewer fish than a standard 20 which is longer.

given that you've already got the tank, my recommendation would be to eliminate the swords, get a few more corydoras and perhaps one dwarf gourami. cory's are actually a shoaling species and you'll find them happier in groups of 5-6 or so.