bristlenose catfish and discus

[lilit]

hi
i have a 7cm bristlnose catfish and it still doesnt have any bristles on its nose. does this mean its a female or is it still to early to develop the bristles. also, if i wanted to get her/him a friend of the opposite sex, is it possible to tell the sex of a bristnose at around 4cm?

2nd question: i have a 55gallon (200L) tank with 5 small discus, 15 tetras, 1 bristlenose, and i might get a 6 corys or 6 ottos. i have a strong internal filter and im going to also get a ehiem 2213 within the next couple of months. ive been reading that 6 is the minimum number to keep..so do you think its ok to get another discus in my tank? will the filtration be enough or will i be pushing it?

[Orange Crush]

Filtaration will not replace water changes and since your tank will definatly be overstocked when the fish you have are bigger you are going to have to do massive daily water changes no matter how much filtration you have. Do not add any more fish to that tank. Get a bigger tank so you can have 6 discus and add cories if you wish. Stay away from oto cats, they will suck on the discus slime coat, esp. when the discus are sleeping.
Either way, if you choose to add more fish you will need to QT them in another tank for 6-8 weeks to prevent illness/death of the fish you currently have.

[lilit]

im happy with the 5 that i have, but i was just thinking of the benefits of getting another one will outweigh the costs? i probably wont get any corys or ottos but i put them in my list because of the possiblity.

i do one water change a week at the least. sometimes twice. is it not worth getting another one or would it be a good idea if i was to cut down on the tetras, stay away from the corys/ottos, and get the ehiem.

thanks

[Orange Crush]

If the 5 you have are getting along without one of them being picked on and stressed out then I would not put a 6th one in that crowded tank. Normally 6 is better to spread out agression but sometimes 5 works. It is always best to get 6 from the get go to avoid problems but if you are lucky enough to have none then stick with what you have.
Do not add any more fish into that tank. Grown discus need 10 gallons each which leaves you with 5 gallons for all of the other fish you already have. You really need a bigger tank or to get rid of the tetras and not add anything else.
Filtration will not help make up for lack of daily water changes no matter how good your filter is. Filters do not remove all that needs to be removed from the water to keep discus healthy. Currently you are not doing enough water changes for young discus and when they are full grown you will need to do daily wc's because your tank will be overcrowded.