My cactus is ill :-(

[emmagleb]

I hope someone knows whats up with Miguel, my cactus. I don't know the technical name, but he's a stereotypical cactus, with very pronounced 'valley/hill' ridges, and thick spikes that are about an inch long at the bottom. He's 5 inches across, and 6 inches tall. I've had him since october, and he's been sat in my room on a bookshelf ever since. I don't get any direct sunlight into my room, so anywhere is the same. I water him every 3-4 weeks, which is what the label said when I was given him. Tonight I noticed that the sunglasses he wears had sagged to one side, and as I straightened them I saw that the green flesh has changed colour to khaki (affecting about 2/3 of it) from the bottom up, and gone all limp and wrinkly. One side is worse than the other, and also has tiny, pin-prick sized black spots in the 'valley' parts. This has only happened in the last few days (I turned him round at the weekend, as I always do so every bit gets even light). I can't think of anything I've done differently, and I'd have thought that if it was lack of sunlight or over watering it would've happened sooner. I've moved him to the back door where we get the most light, and warned my housemates not to kick him over. Anyone got any ideas? Thanks, Emma

[greenfingers]

Black spots sounds like some sort of fungal attack , it sounds pretty grim to me. I think you may have to face the fact that Miguel may not get over this.

[woofgang]

If Miguel is headed for that great mesa in the sky, you might want to try propagating him. here's a website that tells you how, its under "seed" and you need to scroll down.