Black gresheki ailing--old age??

[57spook]

Hi! I have a pressing question. I have 5 African Cichlids that my husband and I have had for 8 years. Yesterday I did my usual weekly water change, tank cleaning. Later last night my husband noticed that Blackie (how original!) was breathing harder than normal. He has no other signs of any sickness. Now I see today he is laying on his side on a plant still breathing heavily. I see no signs of any illness, parasite, injury, etc. There are four other cichlids and one plecostomus and one pictus in the tank and they are all healthy and normal. I did put in our tank divider to keep the others away from him (I hate it when they pick on hurt/sick/dying tankmates). Could this just be old age? They are all about the same age, except the pleco, who is about 11 years old. I don't know what to do for him. Please help! Oh yes, he is one mean &*%, in other words, king of the tank in no uncertain words. That's also why I separated him in case some want to do a little "payback."

[Kuli_Loach]

Has he grown any since you got him? If not then it very well could be.

[gm72]

Certainly sounds as if it is old age.

[57spook]

Update on Blackie. I checked my water parameters and they were:
Ammonia- 0
Nitrates-0
Nitrites-.25
pH-7.6

I have no idea where the nitrites came in as this is a well established tank for 8 years running now and I had just done the weekly clean tank/change water. But anyway, I did come upon a couple of very dirty spots in the tank yesterday, maybe I stirred something up. So I did a 70% water change and on the advice of someone else, added salt; 1T/10g water. Blackie did seem to become more alert and swimming so I took the divider out. It was only a short reprieve. Now one of the Auratus (Stripey) seems to know that he's down and out and keeps chasing and picking fights with Blackie--it seems he is challenging him. Blackie goes for a spurt of energy fighting and chasing, then sinks. So back goes the divider. Now he's just laying on the bottom. I think I'll change the water again to get the salt out as I do have plants in the tank and don't want to harm them too much. Do you suppose he just reacted to the activity and now is worn out? Poor old guy.

[Dixie]

I'm not positive but I think 8 yrs is a long time for a cichlid to live. The salt might have perked him up and I'm not sure that it would hurt you plants at that low of a dosage. Maybe someone else knows better. Hope Blackie pulls through but I like I said 8yrs is probably a good long life.

[57spook]

Well, Blackie is still hanging in there. Blackie gets up once in a while and sinks back down as he did yesterday. So you think 1T/10g salt to water is not too strong for the plants? I could add it back in.