Welcome back to another Foolish review of the hottest stocks, as ranked by Motley Fool CAPS. We're looking at the three best-performing industries over the past 30 days, and your favorite long and short candidates in each.

Last time, renewable fuels firms were blowing up the market. No longer. Multimedia software makers top today's chart, up 36.2% as a group over the past 30 days.

No one else gets close, though fertilizer producers still smell sweet, with a 25.5% average return since mid-December.

And in third place? The molecule men. Manufacturers of molecular diagnostics equipment are up 13.9% over the last month.

According to you, our Foolish readers, the best stocks in these industries to own now -- i.e., those with four or five of the maximum five stars in CAPS -- are:

Company

CAPS Stars

No. of CAPS Ratings

Bull Ratio

30-Day Price Change

ShengdaTech (Nasdaq: SDTH)

*****

574

99.1%

36.2%

GigaMedia (Nasdaq: GIGM)

*****

1,512

98.1%

(6.8%)

LSB Industries (AMEX: LXU)

*****

295

97.6%

10.8%

Activision (Nasdaq: ATVI)

*****

1,445

97.3%

2.0%

Potash Corp (NYSE: POT)

*****

1,268

97.0%

7.1%

Sources: Motley Fool CAPS, Yahoo! Finance.

And your favorite short candidate -- rated with just one star in CAPS:

Company

CAPS Stars

No. of CAPS Ratings

Bear Ratio

30-Day Price Change

Convera (Nasdaq: CNVR)

*

89

84.3%

23.4%

Sources: Motley Fool CAPS, Yahoo! Finance.

Do you agree? Disagree? Let us know what you think by signing up for CAPS today. It's 100% free to participate.

Cap off your day with related CAPS Foolishness:

Activision is a Stock Advisor selection. GigaMedia is a Global Gains recommendation. Try either of these market-beating services free for 30 days. There's no obligation to subscribe.

Fool contributor Tim Beyers, ranked 11,598 out of more than 80,000 total participants in CAPS, didn't own shares in any of the companies mentioned in this article at the time of publication. Find Tim's portfolio here and his latest blog commentary here. The Motley Fool's disclosure policy is hotter than city asphalt in the summer heat.