Live copepods may appear motionless immediately after shipping—this is normal and doesn't mean they're dead:

Why copepods appear inactive after shipping:
- Temperature shock from cold UPS shipping (even in insulated packaging)
- Copepods enter dormant state to conserve energy during stress
- Some species (especially Tisbe) sink to bottle bottom when inactive
- Natural behavior—copepods remain still to avoid predation

How to confirm copepods are alive:

1. Warm the bottle: Let sealed bottle sit at room temperature 20-30 minutes
2. Swirl gently: Don't shake vigorously—gentle swirling distributes copepods
3. Look for ANY movement: Even minimal twitching or slow swimming confirms life
4. Check under bright light: Use flashlight or strong light to spot movement
5. Wait 30-60 minutes: Copepods become increasingly active as they warm

Dead vs. alive copepods:
- Alive: Swimming (even slowly), dark/translucent color, sinking to bottom but responsive to movement
- Dead: Floating at surface, completely motionless after warming, opaque white/gray color, deteriorating appearance

If truly dead on arrival:
Contact sales@getpoddrop.com within 24 hours with photo of opened bottle. Our live arrival guarantee covers 100% replacement or refund for any copepods that don't arrive alive.

Pro tip: Seeing 50-70% active swimming within 30 minutes of warming is normal and healthy. Not every copepod swims constantly—many rest on bottle sides or bottom.

Normal ocean smell vs. contamination—how to tell if your live copepods are healthy:

Normal, healthy phytoplankton/copepod smell:
- Mild ocean/seaweed/marine scent (similar to opening fresh saltwater)
- Slight "green" or "earthy" odor from live phytoplankton cultures
- Faint fishy smell (normal for marine organisms)
- This is normal and indicates healthy, living cultures

Bad smell indicating contamination:
- Strong ammonia smell (sharp, chemical odor)
- Rotten egg/sulfur smell
- Putrid or extremely foul odor
- This indicates bacterial contamination or dead copepods

What to do if bottle smells bad:

1. Check expiration date: Bottles have "use by" dates—expired cultures may develop off odors
2. Inspect visually: Cloudy water, floating copepods, or discoloration indicates problems
3. Contact us immediately: Email photo to sales@getpoddrop.com for replacement under live arrival guarantee
4. Don't add to tank: Contaminated cultures can introduce harmful bacteria to reef aquariums

Storage guidelines to prevent odor:
- Use copepods within 24-48 hours of delivery for best freshness
- Refrigerate at 40-50°F if not using immediately (extends shelf life 3-5 days)
- Keep bottle sealed until ready to use
- Don't expose to direct sunlight or heat

PodDrop cultures are shipped fresh from our Arizona aquaculture facility and should arrive with minimal odor. Any strong unpleasant smell warrants immediate contact for replacement.

Not seeing copepods immediately after adding them is completely normal—they're excellent hiders with natural predator-avoidance behavior:

Why you don't see copepods in reef tanks (even when they're thriving):

- Natural hiding behavior: Copepods burrow deep in live rock pores, crevices fish can't access
- Substrate dwelling: Tisbe biminiensis species lives in sandbed—nearly invisible during day
- Nocturnal activity: Copepods hide during daylight, emerge at night to graze safely
- Small size: Even 2-3mm copepods blend into rockwork and algae
- Fish predation reduced populations: Normal—surviving copepods reproduce to replace consumed individuals

How to confirm copepods established in your tank:

Nighttime inspection (most reliable):
- Wait 1-2 hours after lights-out
- Use flashlight on aquarium glass
- Look for tiny moving specs—those are copepods!
- Healthy populations show dozens to hundreds visible at night

Fish behavior:
- Mandarin fish, wrasses actively picking at rocks = abundant copepods present
- Fish maintaining healthy weight without supplemental feeding

Reproduction timeline:
- Week 1-2: Copepods establishing, mostly hiding
- Week 2-4: Early reproduction beginning, occasional sightings
- Week 4-6: Noticeable population increase
- Week 6-8+: Dense, easily visible populations (if fed phytoplankton regularly)

If you don't see ANY copepods after 4 weeks:

- Check UV sterilizer: Turn off UV for 48 hours (kills planktonic copepods)
- Reduce protein skimming: Aggressive skimmers remove copepod nauplii (larvae)
- Feed live phytoplankton: Without phytoplankton food, copepods can't reproduce
- Evaluate fish predation: Wrasses, dottybacks may be consuming all copepods—add more to refugium

Refugium recommendation: Adding copepods to refugium with macroalgae creates protected breeding populations that continuously reseed display tank despite fish predation.

Remember: Just because you don't see copepods doesn't mean they're gone. They're hiding in rockwork during the day, emerging at night to feed and reproduce.

Yes—UV sterilizers kill free-swimming copepods and copepod larvae (nauplii) that pass through UV chamber:

How UV sterilizers affect copepod populations:

- Planktonic copepods killed: Any copepods swimming in water column that flow through UV are killed by ultraviolet radiation
- Copepod nauplii (larvae) most vulnerable: Microscopic larvae spend more time free-swimming, higher UV exposure
- Adult copepods in rockwork safe: Copepods hiding in live rock, refugium, substrate are unaffected by UV
- Reduces but doesn't eliminate populations: UV kills circulating copepods but can't eliminate hidden breeding populations

Best practices for copepods with UV sterilizers:

When adding new copepods to tank:
1. Turn OFF UV sterilizer 48 hours before adding copepods
2. Add copepods to tank (preferably at night)
3. Keep UV off for 48 hours after adding
4. This allows copepods to establish in rockwork before UV exposure

Long-term UV management for copepod populations:

- Run UV on timer: 6-8 hours daily instead of 24/7 (reduces copepod kill while maintaining pathogen control)
- Reduce UV flow rate: Slower flow through UV chamber means more copepods avoid chamber entirely
- Add refugium: Refugium breeding populations protected from UV continuously reseed display tank
- Supplement regularly: Add fresh copepods every 4-6 weeks to replace UV losses

UV alternatives for copepod-friendly reef tanks:
- Ozone (doesn't kill copepods in rockwork)
- Proper quarantine protocols (prevents disease without constant UV)
- High-quality protein skimming + water changes

Decision point: If maintaining dense copepod populations for mandarin fish is priority, consider turning off UV permanently or running only during disease outbreaks. Many successful reef tanks operate without continuous UV sterilization.

Refugiums are the best solution—UV can't kill copepods in separate refugium chamber, allowing sustainable breeding despite UV in main display tank.

Mandarin fish (dragonets) refusing to eat copepods is concerning—these fish require live copepods as their primary diet. Here's how to troubleshoot:

Common reasons mandarins don't eat copepods:

1. Insufficient copepod density:
- Mandarins need DENSE copepod populations (100+ consumed daily)
- Visual hunters—must actually SEE copepods moving on rocks
- Recommended stocking: 4-6 bottles PodDrop copepods for 75-gallon tank with mandarin
- Solution: Add significantly more copepods, stock refugium heavily

2. Tank too new/copepods not established:
- Copepods need 2-4 weeks to establish visible breeding populations
- Mandarins should ONLY be added to mature tanks (6+ months old) with established copepods
- Solution: Wait 3-4 weeks after adding copepods before introducing mandarin fish

3. Competition from other fish:
- Wrasses, anthias, dottybacks also eat copepods aggressively
- May deplete populations before mandarin finds them
- Solution: Remove competing fish or drastically increase copepod stocking

4. Mandarin already trained on frozen food:
- Rare, but some captive-bred mandarins accept frozen mysis, brine shrimp
- Wild-caught mandarins almost never accept frozen
- Solution: Try PE Mysis, Nutramar Ova (prawn eggs), or other small frozen foods

5. Mandarin is new and stressed:
- Recently added mandarins (within 1-2 weeks) may not feed actively due to stress
- Takes time to discover copepod populations in new tank
- Solution: Give 7-14 days to acclimate, reduce lighting during adjustment period

How to help mandarins find copepods:

- Feed phytoplankton before lights-out: This brings copepods out to feed, making them more visible to mandarins
- Reduce water flow temporarily: Copepods become more visible in calmer water
- Add copepods to display tank directly** (not just refugium): Ensures copepods in areas mandarin hunts
- Observe hunting behavior: Watch mandarin closely—picking at rocks (even if seemingly empty) may indicate successful feeding on microscopic copepods

Critical feeding requirements for mandarin fish:
- Dense, established copepod populations BEFORE adding fish
- Continuous phytoplankton feeding (2-3x weekly minimum) to sustain copepod reproduction
- Large tank (75+ gallons recommended) or refugium for sustainable copepod breeding
- Supplement with additional copepods every 2-4 weeks initially

Warning signs mandarin is starving:
- Sunken belly (most obvious sign)
- Hiding constantly, lethargic behavior
- Weight loss over 2-3 weeks

If mandarin shows signs of starvation, remove to separate tank with high copepod density or return to store. Mandarin fish have very high metabolic rates and will die quickly without adequate copepod food source.

Best practice: Don't add mandarin fish until you consistently see abundant copepods on glass every night with flashlight. This confirms population density sufficient for mandarin survival.

Yes—many reef tank medications are highly toxic to copepods and other invertebrates:

Medications that KILL copepods:

Copper-based treatments (most toxic):
- Cupramine, Copper Power, copper sulfate
- Used for ich (Cryptocaryon), velvet, external parasites on fish
- 100% lethal to all copepods, shrimp, snails, crabs at therapeutic doses
- Copper remains in aquarium rockwork for months even after water changes

Antibiotics:
- Erythromycin, kanamycin, metronidazole
- May harm copepod populations depending on dosage and duration
- **Moderate to high toxicity**—reduces copepod reproduction and survival rates

Formalin/malachite green:
- Used for external parasites, flukes
- Toxic to copepods at treatment concentrations

Medications generally SAFE for copepods:
- Praziquantel (for flatworms, internal parasites)
- Most antiparasitic foods (medicated fish food)
- Hydrogen peroxide spot treatments (localized, short exposure)

How to treat fish disease without killing copepods:

Best practice: Quarantine tank treatment (recommended):
1. Remove sick fish to separate quarantine tank (QT)
2. Treat with copper or antibiotics in QT only
3. Main reef tank copepod populations remain safe and healthy
4. Return fish after 4-6 week treatment/observation period

If treating main reef tank is unavoidable:
1. Remove all invertebrates possible (shrimp, snails, crabs) to holding tank
2. Treat main tank with medications
3. Run carbon filtration for 2-4 weeks after treatment to remove medication residue
4. Test for copper (if used)—must be ZERO before re-adding invertebrates
5. Restock copepods after medication clears system

Rebuilding copepod populations after medication:
- Wait minimum 3-4 weeks after medication treatment ends
- Run carbon, do water changes to ensure medication fully removed
- Test for copper residue with test kit (if copper was used)
- Add fresh PodDrop copepods at 2x normal stocking rate
- Feed live phytoplankton heavily (daily for first 2 weeks) to accelerate reproduction

Prevention is best: Quarantine all new fish for 4-6 weeks before adding to main reef tank. This prevents disease introduction and eliminates need for treating display tank with copepod-toxic medications.

Pro tip: Refugiums help preserve copepod genetics during disease outbreaks. Even if main tank copepods are killed by medications, refugium populations can reseed display after treatment clears.